Measurement device for electrical installations and related methods

ABSTRACT

Techniques are disclosed for measurement devices and methods to obtain various physical and/or electrical parameters in an integrated manner. For example, a measurement device may include a housing, an optical emitter, a sensor, a distance measurement circuit, a length measurement circuit, an electrical meter circuit, a display, an infrared imaging module, and/or a non-thermal imaging module. The device may be conveniently carried and utilized by users to perform a series of distance measurements, wire length measurements, electrical parameter measurements, and/or fault inspections, in an integrated manner without using multiple different devices. In one example, electricians may utilize the device to perform installation of electrical wires and/or other tasks at various locations (e.g., electrical work sites). In another example, electricians may utilize the device to view a thermal image of one or more scenes at such locations for locating potential electrical faults.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/US13/059831 filed Sep. 13, 2013 and entitled “MEASUREMENT DEVICEFOR ELECTRICAL INSTALLATIONS AND RELATED METHODS” which is herebyincorporated by reference in its entirety.

International Patent Application No. PCT/US13/059831 claims the benefitof U.S. Provisional Patent Application No. 61/701,292 filed Sep. 14,2012 and entitled “MEASUREMENT DEVICE FOR ELECTRICAL INSTALLATIONS ANDRELATED METHODS” which is hereby incorporated by reference in itsentirety.

This application claims the benefit of U.S. Provisional PatentApplication No. 61/748,018 filed Dec. 31, 2012 and entitled “COMPACTMULTI-SPECTRUM IMAGING WITH FUSION” which is hereby incorporated byreference in its entirety.

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/477,828 filed Jun. 3, 2009 and entitled “INFRARED CAMERASYSTEMS AND METHODS FOR DUAL SENSOR APPLICATIONS” which is herebyincorporated by reference in its entirety.

This patent application is a continuation-in-part of U.S. patentapplication Ser. No. 13/437,645 filed Apr. 2, 2012 and entitled“INFRARED RESOLUTION AND CONTRAST ENHANCEMENT WITH FUSION” which ishereby incorporated by reference in its entirety.

U.S. patent application Ser. No. 13/437,645 is a continuation-in-part ofU.S. patent application Ser. No. 13/105,765 filed May 11, 2011 andentitled “INFRARED RESOLUTION AND CONTRAST ENHANCEMENT WITH FUSION”which is hereby incorporated by reference in its entirety.

U.S. patent application Ser. No. 13/437,645 also claims the benefit ofU.S. Provisional Patent Application No. 61/473,207 filed Apr. 8, 2011and entitled “INFRARED RESOLUTION AND CONTRAST ENHANCEMENT WITH FUSION”which is hereby incorporated by reference in its entirety.

U.S. patent application Ser. No. 13/437,645 is also acontinuation-in-part of U.S. patent application Ser. No. 12/766,739filed Apr. 23, 2010 and entitled “INFRARED RESOLUTION AND CONTRASTENHANCEMENT WITH FUSION” which is hereby incorporated by reference inits entirety.

U.S. patent application Ser. No. 13/105,765 is a continuation ofInternational Patent Application No. PCT/EP2011/056432 filed Apr. 21,2011 and entitled “INFRARED RESOLUTION AND CONTRAST ENHANCEMENT WITHFUSION” which is hereby incorporated by reference in its entirety.

U.S. patent application Ser. No. 13/105,765 is also acontinuation-in-part of U.S. patent application Ser. No. 12/766,739which is hereby incorporated by reference in its entirety.

International Patent Application No. PCT/EP2011/056432 is acontinuation-in-part of U.S. patent application Ser. No. 12/766,739which is hereby incorporated by reference in its entirety.

International Patent Application No. PCT/EP2011/056432 also claims thebenefit of U.S. Provisional Patent Application No. 61/473,207 which ishereby incorporated by reference in its entirety.

This application is a continuation-in-part of International PatentApplication No. PCT/US2012/041744 filed Jun. 8, 2012 and entitled “LOWPOWER AND SMALL FORM FACTOR INFRARED IMAGING” which is herebyincorporated by reference in its entirety.

International Patent Application No. PCT/US2012/041744 claims thebenefit of U.S. Provisional Patent Application No. 61/656,889 filed Jun.7, 2012 and entitled “LOW POWER AND SMALL FORM FACTOR INFRARED IMAGING”which is hereby incorporated by reference in its entirety.

International Patent Application No. PCT/US2012/041744 claims thebenefit of U.S. Provisional Patent Application No. 61/545,056 filed Oct.7, 2011 and entitled “NON-UNIFORMITY CORRECTION TECHNIQUES FOR INFRAREDIMAGING DEVICES” which is hereby incorporated by reference in itsentirety.

International Patent Application No. PCT/US2012/041744 claims thebenefit of U.S. Provisional Patent Application No. 61/495,873 filed Jun.10, 2011 and entitled “INFRARED CAMERA PACKAGING SYSTEMS AND METHODS”which is hereby incorporated by reference in its entirety.

International Patent Application No. PCT/US2012/041744 claims thebenefit of U.S. Provisional Patent Application No. 61/495,879 filed Jun.10, 2011 and entitled “INFRARED CAMERA SYSTEM ARCHITECTURES” which ishereby incorporated by reference in its entirety.

International Patent Application No. PCT/US2012/041744 claims thebenefit of U.S. Provisional Patent Application No. 61/495,888 filed Jun.10, 2011 and entitled “INFRARED CAMERA CALIBRATION TECHNIQUES” which ishereby incorporated by reference in its entirety.

This application is a continuation-in-part of International PatentApplication No. PCT/US2012/041749 filed Jun. 8, 2012 and entitled“NON-UNIFORMITY CORRECTION TECHNIQUES FOR INFRARED IMAGING DEVICES”which is hereby incorporated by reference in its entirety.

International Patent Application No. PCT/US2012/041749 claims thebenefit of U.S. Provisional Patent Application No. 61/545,056 filed Oct.7, 2011 and entitled “NON-UNIFORMITY CORRECTION TECHNIQUES FOR INFRAREDIMAGING DEVICES” which is hereby incorporated by reference in itsentirety.

International Patent Application No. PCT/US2012/041749 claims thebenefit of U.S. Provisional Patent Application No. 61/495,873 filed Jun.10, 2011 and entitled “INFRARED CAMERA PACKAGING SYSTEMS AND METHODS”which is hereby incorporated by reference in its entirety.

International Patent Application No. PCT/US2012/041749 claims thebenefit of U.S. Provisional Patent Application No. 61/495,879 filed Jun.10, 2011 and entitled “INFRARED CAMERA SYSTEM ARCHITECTURES” which ishereby incorporated by reference in its entirety.

International Patent Application No. PCT/US2012/041749 claims thebenefit of U.S. Provisional Patent Application No. 61/495,888 filed Jun.10, 2011 and entitled “INFRARED CAMERA CALIBRATION TECHNIQUES” which ishereby incorporated by reference in its entirety.

This application is a continuation-in-part of International PatentApplication No. PCT/US2012/041739 filed Jun. 8, 2012 and entitled“INFRARED CAMERA SYSTEM ARCHITECTURES” which is hereby incorporated byreference in its entirety.

International Patent Application No. PCT/US2012/041739 claims thebenefit of U.S. Provisional Patent Application No. 61/495,873 filed Jun.10, 2011 and entitled “INFRARED CAMERA PACKAGING SYSTEMS AND METHODS”which is hereby incorporated by reference in its entirety.

International Patent Application No. PCT/US2012/041739 claims thebenefit of U.S. Provisional Patent Application No. 61/495,879 filed Jun.10, 2011 and entitled “INFRARED CAMERA SYSTEM ARCHITECTURES” which ishereby incorporated by reference in its entirety.

International Patent Application No. PCT/US2012/041739 claims thebenefit of U.S. Provisional Patent Application No. 61/495,888 filed Jun.10, 2011 and entitled “INFRARED CAMERA CALIBRATION TECHNIQUES” which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

One or more embodiments of the invention relate generally to measuringinstruments and more particularly, for example, to instruments providingphysical and/or electrical parameter measurements.

BACKGROUND

Electrical installation, repair, or maintenance work typically requireselectricians and other persons to perform a series of measurements andinspections while at work sites. For example, an electrician may need toprecisely measure various distances or spans of electrical wireinstallation locations to determine the length of wires required,inspect a wire spool to check whether there is a wire long enoughremaining on the spool, and check the length of a cut wire beforeinstalling it at the installation location. Further, after installationof the wire and/or other electrical components, the electrician may needto scan the installation location for hot spots or cold spots that mayindicate various types of electrical faults, and then check variouselectrical parameters (e.g., a voltage, current, resistance,capacitance, or other parameter) of specific wires or components whereelectrical faults are suspected.

However, electricians typically limit themselves to carrying a singledevice with limited capabilities (e.g., a multimeter) to work sitesbecause of the unavailability of other instruments and/or theinconvenience of carrying and switching between multiple instruments.Further, conventional devices used for electrical work typically do notprovide thermal imaging capabilities to perform fault detection andother tasks.

SUMMARY

Various techniques are disclosed for measurement devices and methods toobtain various physical and/or electrical parameters in an integratedmanner. For example, in accordance with various embodiments of thedisclosure, a measurement device may include a housing, an opticalemitter, a sensor, a distance measurement circuit, a length measurementcircuit, an electrical meter circuit, a display, an infrared imagingmodule, and/or a non-thermal imaging module. The measurement device maybe conveniently carried and utilized by users to perform a series ofdistance measurements, wire length measurements, electrical parametermeasurements, and/or fault inspections, in an integrated manner withoutusing multiple different devices. In one example, electricians mayutilize the measurement device to perform installation of electricalwires and/or other tasks at various locations (e.g., for field operationat electrical work sites such as, for example, electrical inspection orinstallation sites, and/or other locations). In another example,electricians may utilize the measurement device to view a thermal imageof one or more scenes at such locations for conveniently locatingpotential electrical faults.

In one embodiment, a measurement device includes a housing adapted to behand-held by a user; a logic device adapted to determine a physicalparameter associated with an external article; an infrared imagingmodule adapted to capture an infrared image of a scene; and a displayfixed relative to the housing and adapted to overlay informationindicative of the physical electrical parameter onto the a user-viewableimage, converted from the captured infrared image, to display theinformation and the user-viewable image for viewing by the user.

In another embodiment, a measurement device includes a housingconfigured to be hand-held by a user; an optical emitter configured totransmit an optical beam to a target in a scene; a sensor configured todetect the optical beam as reflected from the target and to generate adetection signal in response to the detected optical pulse; a distancemeasurement circuit configured to determine a distance to the targetbased on the detection signal; an electrical meter circuit configured tobe electrically connected to an external article and to determine anelectrical parameter associated with the external article; and a displayconfigured to present information indicative of the distance and/or theelectrical parameter for viewing by the user.

In another embodiment, a method includes transmitting an optical beam toa target using an optical emitter of a measurement device configured tobe hand-held by a user, wherein the optical beam is aimed at the targetby the user; detecting the optical beam as reflected off the targetusing a sensor of the device; generating a detection signal in responseto the detected optical beam; determining, by a distance measurementcircuit of the device, a distance to the target based on the detectionsignal; presenting, for viewing by the user on a display of the device,information indicative of the distance to the target; determining, by anelectrical meter circuit of the device, an electrical parameter of anexternal article electrically connected to the electrical meter circuit;and presenting, for viewing by the user on the display, informationindicative of the electrical parameter.

The scope of the invention is defined by the claims, which areincorporated into this section by reference. A more completeunderstanding of embodiments of the invention will be afforded to thoseskilled in the art, as well as a realization of additional advantagesthereof, by a consideration of the following detailed description of oneor more embodiments. Reference will be made to the appended sheets ofdrawings that will first be described briefly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an infrared imaging module configured to beimplemented in a host device in accordance with an embodiment of thedisclosure.

FIG. 2 illustrates an assembled infrared imaging module in accordancewith an embodiment of the disclosure.

FIG. 3 illustrates an exploded view of an infrared imaging modulejuxtaposed over a socket in accordance with an embodiment of thedisclosure.

FIG. 4 illustrates a block diagram of an infrared sensor assemblyincluding an array of infrared sensors in accordance with an embodimentof the disclosure.

FIG. 5 illustrates a flow diagram of various operations to determine NUCterms in accordance with an embodiment of the disclosure.

FIG. 6 illustrates differences between neighboring pixels in accordancewith an embodiment of the disclosure.

FIG. 7 illustrates a flat field correction technique in accordance withan embodiment of the disclosure.

FIG. 8 illustrates various image processing techniques of FIG. 5 andother operations applied in an image processing pipeline in accordancewith an embodiment of the disclosure.

FIG. 9 illustrates a temporal noise reduction process in accordance withan embodiment of the disclosure.

FIG. 10 illustrates particular implementation details of severalprocesses of the image processing pipeline of FIG. 6 in accordance withan embodiment of the disclosure.

FIG. 11 illustrates spatially correlated FPN in a neighborhood of pixelsin accordance with an embodiment of the disclosure.

FIG. 12 illustrates a block diagram of another implementation of aninfrared sensor assembly including an array of infrared sensors and alow-dropout regulator in accordance with an embodiment of thedisclosure.

FIG. 13 illustrates a circuit diagram of a portion of the infraredsensor assembly of FIG. 12 in accordance with an embodiment of thedisclosure.

FIG. 14A illustrates a front exterior view of a measurement device inaccordance with an embodiment of the disclosure.

FIG. 14B illustrates a top exterior view of the measurement device ofFIG. 14A, in accordance with an embodiment of the disclosure.

FIG. 15 illustrates a block diagram of the measurement device of FIG.14A, in accordance with an embodiment of the disclosure.

FIG. 16 illustrates a block diagram of a measurement device inaccordance with another embodiment of the disclosure.

FIG. 17 illustrates a front exterior view of a measurement device inaccordance with an embodiment of the disclosure.

FIG. 18 illustrates a front exterior view of a measurement device inaccordance with another embodiment of the disclosure.

FIG. 19 illustrates a flowchart of a process to combine thermal imagesand non-thermal images in accordance with an embodiment of thedisclosure.

FIG. 20 illustrates a flowchart of a process to perform measurements andinspections using a measurement device in accordance with an embodimentof the disclosure.

FIG. 21 illustrates a flowchart of a process to manufacture ameasurement device in accordance with an embodiment of the disclosure.

Embodiments of the invention and their advantages are best understood byreferring to the detailed description that follows. It should beappreciated that like reference numerals are used to identify likeelements illustrated in one or more of the figures.

DETAILED DESCRIPTION

FIG. 1 illustrates an infrared imaging module 100 (e.g., an infraredcamera or an infrared imaging device) configured to be implemented in ahost device 102 in accordance with an embodiment of the disclosure.Infrared imaging module 100 may be implemented, for one or moreembodiments, with a small form factor and in accordance with wafer levelpackaging techniques or other packaging techniques.

In one embodiment, infrared imaging module 100 may be configured to beimplemented in a small portable host device 102, such as a mobiletelephone, a tablet computing device, a laptop computing device, apersonal digital assistant, a visible light camera, a music player, orany other appropriate mobile device. In this regard, infrared imagingmodule 100 may be used to provide infrared imaging features to hostdevice 102. For example, infrared imaging module 100 may be configuredto capture, process, and/or otherwise manage infrared images and providesuch infrared images to host device 102 for use in any desired fashion(e.g., for further processing, to store in memory, to display, to use byvarious applications running on host device 102, to export to otherdevices, or other uses).

In various embodiments, infrared imaging module 100 may be configured tooperate at low voltage levels and over a wide temperature range. Forexample, in one embodiment, infrared imaging module 100 may operateusing a power supply of approximately 2.4 volts, 2.5 volts, 2.8 volts,or lower voltages, and operate over a temperature range of approximately−20 degrees C. to approximately +60 degrees C. (e.g., providing asuitable dynamic range and performance over an environmental temperaturerange of approximately 80 degrees C.). In one embodiment, by operatinginfrared imaging module 100 at low voltage levels, infrared imagingmodule 100 may experience reduced amounts of self heating in comparisonwith other types of infrared imaging devices. As a result, infraredimaging module 100 may be operated with reduced measures to compensatefor such self heating.

As shown in FIG. 1, host device 102 may include a socket 104, a shutter105, motion sensors 194, a processor 195, a memory 196, a display 197,and/or other components 198. Socket 104 may be configured to receiveinfrared imaging module 100 as identified by arrow 101. In this regard,FIG. 2 illustrates infrared imaging module 100 assembled in socket 104in accordance with an embodiment of the disclosure.

Motion sensors 194 may be implemented by one or more accelerometers,gyroscopes, or other appropriate devices that may be used to detectmovement of host device 102. Motion sensors 194 may be monitored by andprovide information to processing module 160 or processor 195 to detectmotion. In various embodiments, motion sensors 194 may be implemented aspart of host device 102 (as shown in FIG. 1), infrared imaging module100, or other devices attached to or otherwise interfaced with hostdevice 102.

Processor 195 may be implemented as any appropriate device (e.g.,programmable logic device, microcontroller, processor, applicationspecific integrated circuit (ASIC), or other device) that may be used byhost device 102 to execute appropriate instructions, such as softwareinstructions provided in memory 196. Display 197 may be used to displaycaptured and/or processed infrared images and/or other images, data, andinformation. Other components 198 may be used to implement any featuresof host device 102 as may be desired for various applications (e.g.,clocks, temperature sensors, a visible light camera, or othercomponents). In addition, a machine readable medium 193 may be providedfor storing non-transitory instructions for loading into memory 196 andexecution by processor 195.

In various embodiments, infrared imaging module 100 and socket 104 maybe implemented for mass production to facilitate high volumeapplications, such as for implementation in mobile telephones or otherdevices (e.g., requiring small form factors). In one embodiment, thecombination of infrared imaging module 100 and socket 104 may exhibitoverall dimensions of approximately 8.5 mm by 8.5 mm by 5.9 mm whileinfrared imaging module 100 is installed in socket 104.

FIG. 3 illustrates an exploded view of infrared imaging module 100juxtaposed over socket 104 in accordance with an embodiment of thedisclosure. Infrared imaging module 100 may include a lens barrel 110, ahousing 120, an infrared sensor assembly 128, a circuit board 170, abase 150, and a processing module 160.

Lens barrel 110 may at least partially enclose an optical element 180(e.g., a lens) which is partially visible in FIG. 3 through an aperture112 in lens barrel 110. Lens barrel 110 may include a substantiallycylindrical extension 114 which may be used to interface lens barrel 110with an aperture 122 in housing 120.

Infrared sensor assembly 128 may be implemented, for example, with a cap130 (e.g., a lid) mounted on a substrate 140. Infrared sensor assembly128 may include a plurality of infrared sensors 132 (e.g., infrareddetectors) implemented in an array or other fashion on substrate 140 andcovered by cap 130. For example, in one embodiment, infrared sensorassembly 128 may be implemented as a focal plane array (FPA). Such afocal plane array may be implemented, for example, as a vacuum packageassembly (e.g., sealed by cap 130 and substrate 140). In one embodiment,infrared sensor assembly 128 may be implemented as a wafer level package(e.g., infrared sensor assembly 128 may be singulated from a set ofvacuum package assemblies provided on a wafer). In one embodiment,infrared sensor assembly 128 may be implemented to operate using a powersupply of approximately 2.4 volts, 2.5 volts, 2.8 volts, or similarvoltages.

Infrared sensors 132 may be configured to detect infrared radiation(e.g., infrared energy) from a target scene including, for example, midwave infrared wave bands (MWIR), long wave infrared wave bands (LWIR),and/or other thermal imaging bands as may be desired in particularimplementations. In one embodiment, infrared sensor assembly 128 may beprovided in accordance with wafer level packaging techniques.

Infrared sensors 132 may be implemented, for example, as microbolometersor other types of thermal imaging infrared sensors arranged in anydesired array pattern to provide a plurality of pixels. In oneembodiment, infrared sensors 132 may be implemented as vanadium oxide(VOx) detectors with a 17 μm pixel pitch. In various embodiments, arraysof approximately 32 by 32 infrared sensors 132, approximately 64 by 64infrared sensors 132, approximately 80 by 64 infrared sensors 132, orother array sizes may be used.

Substrate 140 may include various circuitry including, for example, aread out integrated circuit (ROIC) with dimensions less thanapproximately 5.5 mm by 5.5 mm in one embodiment. Substrate 140 may alsoinclude bond pads 142 that may be used to contact complementaryconnections positioned on inside surfaces of housing 120 when infraredimaging module 100 is assembled as shown in FIGS. 5A, 5B, and 5C. In oneembodiment, the ROIC may be implemented with low-dropout regulators(LDO) to perform voltage regulation to reduce power supply noiseintroduced to infrared sensor assembly 128 and thus provide an improvedpower supply rejection ratio (PSRR). Moreover, by implementing the LDOwith the ROIC (e.g., within a wafer level package), less die area may beconsumed and fewer discrete die (or chips) are needed.

FIG. 4 illustrates a block diagram of infrared sensor assembly 128including an array of infrared sensors 132 in accordance with anembodiment of the disclosure. In the illustrated embodiment, infraredsensors 132 are provided as part of a unit cell array of a ROIC 402.ROIC 402 includes bias generation and timing control circuitry 404,column amplifiers 405, a column multiplexer 406, a row multiplexer 408,and an output amplifier 410. Image frames (e.g., thermal images)captured by infrared sensors 132 may be provided by output amplifier 410to processing module 160, processor 195, and/or any other appropriatecomponents to perform various processing techniques described herein.Although an 8 by 8 array is shown in FIG. 4, any desired arrayconfiguration may be used in other embodiments. Further descriptions ofROICs and infrared sensors (e.g., microbolometer circuits) may be foundin U.S. Pat. No. 6,028,309 issued Feb. 22, 2000, which is incorporatedherein by reference in its entirety.

Infrared sensor assembly 128 may capture images (e.g., image frames) andprovide such images from its ROIC at various rates. Processing module160 may be used to perform appropriate processing of captured infraredimages and may be implemented in accordance with any appropriatearchitecture. In one embodiment, processing module 160 may beimplemented as an ASIC. In this regard, such an ASIC may be configuredto perform image processing with high performance and/or highefficiency. In another embodiment, processing module 160 may beimplemented with a general purpose central processing unit (CPU) whichmay be configured to execute appropriate software instructions toperform image processing, coordinate and perform image processing withvarious image processing blocks, coordinate interfacing betweenprocessing module 160 and host device 102, and/or other operations. Inyet another embodiment, processing module 160 may be implemented with afield programmable gate array (FPGA). Processing module 160 may beimplemented with other types of processing and/or logic circuits inother embodiments as would be understood by one skilled in the art.

In these and other embodiments, processing module 160 may also beimplemented with other components where appropriate, such as, volatilememory, non-volatile memory, and/or one or more interfaces (e.g.,infrared detector interfaces, inter-integrated circuit (I2C) interfaces,mobile industry processor interfaces (MIPI), joint test action group(JTAG) interfaces (e.g., IEEE 1149.1 standard test access port andboundary-scan architecture), and/or other interfaces).

In some embodiments, infrared imaging module 100 may further include oneor more actuators 199 which may be used to adjust the focus of infraredimage frames captured by infrared sensor assembly 128. For example,actuators 199 may be used to move optical element 180, infrared sensors132, and/or other components relative to each other to selectively focusand defocus infrared image frames in accordance with techniquesdescribed herein. Actuators 199 may be implemented in accordance withany type of motion-inducing apparatus or mechanism, and may positionedat any location within or external to infrared imaging module 100 asappropriate for different applications.

When infrared imaging module 100 is assembled, housing 120 maysubstantially enclose infrared sensor assembly 128, base 150, andprocessing module 160. Housing 120 may facilitate connection of variouscomponents of infrared imaging module 100. For example, in oneembodiment, housing 120 may provide electrical connections 126 toconnect various components as further described.

Electrical connections 126 (e.g., conductive electrical paths, traces,or other types of connections) may be electrically connected with bondpads 142 when infrared imaging module 100 is assembled. In variousembodiments, electrical connections 126 may be embedded in housing 120,provided on inside surfaces of housing 120, and/or otherwise provided byhousing 120. Electrical connections 126 may terminate in connections 124protruding from the bottom surface of housing 120 as shown in FIG. 3.Connections 124 may connect with circuit board 170 when infrared imagingmodule 100 is assembled (e.g., housing 120 may rest atop circuit board170 in various embodiments). Processing module 160 may be electricallyconnected with circuit board 170 through appropriate electricalconnections. As a result, infrared sensor assembly 128 may beelectrically connected with processing module 160 through, for example,conductive electrical paths provided by: bond pads 142, complementaryconnections on inside surfaces of housing 120, electrical connections126 of housing 120, connections 124, and circuit board 170.Advantageously, such an arrangement may be implemented without requiringwire bonds to be provided between infrared sensor assembly 128 andprocessing module 160.

In various embodiments, electrical connections 126 in housing 120 may bemade from any desired material (e.g., copper or any other appropriateconductive material). In one embodiment, electrical connections 126 mayaid in dissipating heat from infrared imaging module 100.

Other connections may be used in other embodiments. For example, in oneembodiment, sensor assembly 128 may be attached to processing module 160through a ceramic board that connects to sensor assembly 128 by wirebonds and to processing module 160 by a ball grid array (BGA). Inanother embodiment, sensor assembly 128 may be mounted directly on arigid flexible board and electrically connected with wire bonds, andprocessing module 160 may be mounted and connected to the rigid flexibleboard with wire bonds or a BGA.

The various implementations of infrared imaging module 100 and hostdevice 102 set forth herein are provided for purposes of example, ratherthan limitation. In this regard, any of the various techniques describedherein may be applied to any infrared camera system, infrared imager, orother device for performing infrared/thermal imaging.

Substrate 140 of infrared sensor assembly 128 may be mounted on base150. In various embodiments, base 150 (e.g., a pedestal) may be made,for example, of copper formed by metal injection molding (MIM) andprovided with a black oxide or nickel-coated finish. In variousembodiments, base 150 may be made of any desired material, such as forexample zinc, aluminum, or magnesium, as desired for a given applicationand may be formed by any desired applicable process, such as for examplealuminum casting, MIM, or zinc rapid casting, as may be desired forparticular applications. In various embodiments, base 150 may beimplemented to provide structural support, various circuit paths,thermal heat sink properties, and other features where appropriate. Inone embodiment, base 150 may be a multi-layer structure implemented atleast in part using ceramic material.

In various embodiments, circuit board 170 may receive housing 120 andthus may physically support the various components of infrared imagingmodule 100. In various embodiments, circuit board 170 may be implementedas a printed circuit board (e.g., an FR4 circuit board or other types ofcircuit boards), a rigid or flexible interconnect (e.g., tape or othertype of interconnects), a flexible circuit substrate, a flexible plasticsubstrate, or other appropriate structures. In various embodiments, base150 may be implemented with the various features and attributesdescribed for circuit board 170, and vice versa.

Socket 104 may include a cavity 106 configured to receive infraredimaging module 100 (e.g., as shown in the assembled view of FIG. 2).Infrared imaging module 100 and/or socket 104 may include appropriatetabs, arms, pins, fasteners, or any other appropriate engagement memberswhich may be used to secure infrared imaging module 100 to or withinsocket 104 using friction, tension, adhesion, and/or any otherappropriate manner. Socket 104 may include engagement members 107 thatmay engage surfaces 109 of housing 120 when infrared imaging module 100is inserted into a cavity 106 of socket 104. Other types of engagementmembers may be used in other embodiments.

Infrared imaging module 100 may be electrically connected with socket104 through appropriate electrical connections (e.g., contacts, pins,wires, or any other appropriate connections). For example, socket 104may include electrical connections 108 which may contact correspondingelectrical connections of infrared imaging module 100 (e.g.,interconnect pads, contacts, or other electrical connections on side orbottom surfaces of circuit board 170, bond pads 142 or other electricalconnections on base 150, or other connections). Electrical connections108 may be made from any desired material (e.g., copper or any otherappropriate conductive material). In one embodiment, electricalconnections 108 may be mechanically biased to press against electricalconnections of infrared imaging module 100 when infrared imaging module100 is inserted into cavity 106 of socket 104. In one embodiment,electrical connections 108 may at least partially secure infraredimaging module 100 in socket 104. Other types of electrical connectionsmay be used in other embodiments.

Socket 104 may be electrically connected with host device 102 throughsimilar types of electrical connections. For example, in one embodiment,host device 102 may include electrical connections (e.g., solderedconnections, snap-in connections, or other connections) that connectwith electrical connections 108 passing through apertures 190. Invarious embodiments, such electrical connections may be made to thesides and/or bottom of socket 104.

Various components of infrared imaging module 100 may be implementedwith flip chip technology which may be used to mount components directlyto circuit boards without the additional clearances typically needed forwire bond connections. Flip chip connections may be used, as an example,to reduce the overall size of infrared imaging module 100 for use incompact small form factor applications. For example, in one embodiment,processing module 160 may be mounted to circuit board 170 using flipchip connections. For example, infrared imaging module 100 may beimplemented with such flip chip configurations.

In various embodiments, infrared imaging module 100 and/or associatedcomponents may be implemented in accordance with various techniques(e.g., wafer level packaging techniques) as set forth in U.S. patentapplication Ser. No. 12/844,124 filed Jul. 27, 2010, and U.S.Provisional Patent Application No. 61/469,651 filed Mar. 30, 2011, whichare incorporated herein by reference in their entirety. Furthermore, inaccordance with one or more embodiments, infrared imaging module 100and/or associated components may be implemented, calibrated, tested,and/or used in accordance with various techniques, such as for exampleas set forth in U.S. Pat. No. 7,470,902 issued Dec. 30, 2008, U.S. Pat.No. 6,028,309 issued Feb. 22, 2000, U.S. Pat. No. 6,812,465 issued Nov.2, 2004, U.S. Pat. No. 7,034,301 issued Apr. 25, 2006, U.S. Pat. No.7,679,048 issued Mar. 16, 2010, U.S. Pat. No. 7,470,904 issued Dec. 30,2008, U.S. patent application Ser. No. 12/202,880 filed Sep. 2, 2008,and U.S. patent application Ser. No. 12/202,896 filed Sep. 2, 2008,which are incorporated herein by reference in their entirety.

Referring again to FIG. 1, in various embodiments, host device 102 mayinclude shutter 105. In this regard, shutter 105 may be selectivelypositioned over socket 104 (e.g., as identified by arrows 103) whileinfrared imaging module 100 is installed therein. In this regard,shutter 105 may be used, for example, to protect infrared imaging module100 when not in use. Shutter 105 may also be used as a temperaturereference as part of a calibration process (e.g., a NUC process or othercalibration processes) for infrared imaging module 100 as would beunderstood by one skilled in the art.

In various embodiments, shutter 105 may be made from various materialssuch as, for example, polymers, glass, aluminum (e.g., painted oranodized) or other materials. In various embodiments, shutter 105 mayinclude one or more coatings to selectively filter electromagneticradiation and/or adjust various optical properties of shutter 105 (e.g.,a uniform blackbody coating or a reflective gold coating).

In another embodiment, shutter 105 may be fixed in place to protectinfrared imaging module 100 at all times. In this case, shutter 105 or aportion of shutter 105 may be made from appropriate materials (e.g.,polymers or infrared transmitting materials such as silicon, germanium,zinc selenide, or chalcogenide glasses) that do not substantially filterdesired infrared wavelengths. In another embodiment, a shutter may beimplemented as part of infrared imaging module 100 (e.g., within or aspart of a lens barrel or other components of infrared imaging module100), as would be understood by one skilled in the art.

Alternatively, in another embodiment, a shutter (e.g., shutter 105 orother type of external or internal shutter) need not be provided, butrather a NUC process or other type of calibration may be performed usingshutterless techniques. In another embodiment, a NUC process or othertype of calibration using shutterless techniques may be performed incombination with shutter-based techniques.

Infrared imaging module 100 and host device 102 may be implemented inaccordance with any of the various techniques set forth in U.S.Provisional Patent Application No. 61/495,873 filed Jun. 10, 2011, U.S.Provisional Patent Application No. 61/495,879 filed Jun. 10, 2011, andU.S. Provisional Patent Application No. 61/495,888 filed Jun. 10, 2011,which are incorporated herein by reference in their entirety.

In various embodiments, the components of host device 102 and/orinfrared imaging module 100 may be implemented as a local or distributedsystem with components in communication with each other over wiredand/or wireless networks. Accordingly, the various operations identifiedin this disclosure may be performed by local and/or remote components asmay be desired in particular implementations.

FIG. 5 illustrates a flow diagram of various operations to determine NUCterms in accordance with an embodiment of the disclosure. In someembodiments, the operations of FIG. 5 may be performed by processingmodule 160 or processor 195 (both also generally referred to as aprocessor) operating on image frames captured by infrared sensors 132.

In block 505, infrared sensors 132 begin capturing image frames of ascene. Typically, the scene will be the real world environment in whichhost device 102 is currently located. In this regard, shutter 105 (ifoptionally provided) may be opened to permit infrared imaging module toreceive infrared radiation from the scene. Infrared sensors 132 maycontinue capturing image frames during all operations shown in FIG. 5.In this regard, the continuously captured image frames may be used forvarious operations as further discussed. In one embodiment, the capturedimage frames may be temporally filtered (e.g., in accordance with theprocess of block 826 further described herein with regard to FIG. 8) andbe processed by other terms (e.g., factory gain terms 812, factoryoffset terms 816, previously determined NUC terms 817, column FPN terms820, and row FPN terms 824 as further described herein with regard toFIG. 8) before they are used in the operations shown in FIG. 5.

In block 510, a NUC process initiating event is detected. In oneembodiment, the NUC process may be initiated in response to physicalmovement of host device 102. Such movement may be detected, for example,by motion sensors 194 which may be polled by a processor. In oneexample, a user may move host device 102 in a particular manner, such asby intentionally waving host device 102 back and forth in an “erase” or“swipe” movement. In this regard, the user may move host device 102 inaccordance with a predetermined speed and direction (velocity), such asin an up and down, side to side, or other pattern to initiate the NUCprocess. In this example, the use of such movements may permit the userto intuitively operate host device 102 to simulate the “erasing” ofnoise in captured image frames.

In another example, a NUC process may be initiated by host device 102 ifmotion exceeding a threshold value is exceeded (e.g., motion greaterthan expected for ordinary use). It is contemplated that any desiredtype of spatial translation of host device 102 may be used to initiatethe NUC process.

In yet another example, a NUC process may be initiated by host device102 if a minimum time has elapsed since a previously performed NUCprocess. In a further example, a NUC process may be initiated by hostdevice 102 if infrared imaging module 100 has experienced a minimumtemperature change since a previously performed NUC process. In a stillfurther example, a NUC process may be continuously initiated andrepeated.

In block 515, after a NUC process initiating event is detected, it isdetermined whether the NUC process should actually be performed. In thisregard, the NUC process may be selectively initiated based on whetherone or more additional conditions are met. For example, in oneembodiment, the NUC process may not be performed unless a minimum timehas elapsed since a previously performed NUC process. In anotherembodiment, the NUC process may not be performed unless infrared imagingmodule 100 has experienced a minimum temperature change since apreviously performed NUC process. Other criteria or conditions may beused in other embodiments. If appropriate criteria or conditions havebeen met, then the flow diagram continues to block 520. Otherwise, theflow diagram returns to block 505.

In the NUC process, blurred image frames may be used to determine NUCterms which may be applied to captured image frames to correct for FPN.As discussed, in one embodiment, the blurred image frames may beobtained by accumulating multiple image frames of a moving scene (e.g.,captured while the scene and/or the thermal imager is in motion). Inanother embodiment, the blurred image frames may be obtained bydefocusing an optical element or other component of the thermal imager.

Accordingly, in block 520 a choice of either approach is provided. Ifthe motion-based approach is used, then the flow diagram continues toblock 525. If the defocus-based approach is used, then the flow diagramcontinues to block 530.

Referring now to the motion-based approach, in block 525 motion isdetected. For example, in one embodiment, motion may be detected basedon the image frames captured by infrared sensors 132. In this regard, anappropriate motion detection process (e.g., an image registrationprocess, a frame-to-frame difference calculation, or other appropriateprocess) may be applied to captured image frames to determine whethermotion is present (e.g., whether static or moving image frames have beencaptured). For example, in one embodiment, it can be determined whetherpixels or regions around the pixels of consecutive image frames havechanged more than a user defined amount (e.g., a percentage and/orthreshold value). If at least a given percentage of pixels have changedby at least the user defined amount, then motion will be detected withsufficient certainty to proceed to block 535.

In another embodiment, motion may be determined on a per pixel basis,wherein only pixels that exhibit significant changes are accumulated toprovide the blurred image frame. For example, counters may be providedfor each pixel and used to ensure that the same number of pixel valuesare accumulated for each pixel, or used to average the pixel valuesbased on the number of pixel values actually accumulated for each pixel.Other types of image-based motion detection may be performed such asperforming a Radon transform.

In another embodiment, motion may be detected based on data provided bymotion sensors 194. In one embodiment, such motion detection may includedetecting whether host device 102 is moving along a relatively straighttrajectory through space. For example, if host device 102 is movingalong a relatively straight trajectory, then it is possible that certainobjects appearing in the imaged scene may not be sufficiently blurred(e.g., objects in the scene that may be aligned with or movingsubstantially parallel to the straight trajectory). Thus, in such anembodiment, the motion detected by motion sensors 194 may be conditionedon host device 102 exhibiting, or not exhibiting, particulartrajectories.

In yet another embodiment, both a motion detection process and motionsensors 194 may be used. Thus, using any of these various embodiments, adetermination can be made as to whether or not each image frame wascaptured while at least a portion of the scene and host device 102 werein motion relative to each other (e.g., which may be caused by hostdevice 102 moving relative to the scene, at least a portion of the scenemoving relative to host device 102, or both).

It is expected that the image frames for which motion was detected mayexhibit some secondary blurring of the captured scene (e.g., blurredthermal image data associated with the scene) due to the thermal timeconstants of infrared sensors 132 (e.g., microbolometer thermal timeconstants) interacting with the scene movement.

In block 535, image frames for which motion was detected areaccumulated. For example, if motion is detected for a continuous seriesof image frames, then the image frames of the series may be accumulated.As another example, if motion is detected for only some image frames,then the non-moving image frames may be skipped and not included in theaccumulation. Thus, a continuous or discontinuous set of image framesmay be selected to be accumulated based on the detected motion.

In block 540, the accumulated image frames are averaged to provide ablurred image frame. Because the accumulated image frames were capturedduring motion, it is expected that actual scene information will varybetween the image frames and thus cause the scene information to befurther blurred in the resulting blurred image frame (block 545).

In contrast, FPN (e.g., caused by one or more components of infraredimaging module 100) will remain fixed over at least short periods oftime and over at least limited changes in scene irradiance duringmotion. As a result, image frames captured in close proximity in timeand space during motion will suffer from identical or at least verysimilar FPN. Thus, although scene information may change in consecutiveimage frames, the FPN will stay essentially constant. By averaging,multiple image frames captured during motion will blur the sceneinformation, but will not blur the FPN. As a result, FPN will remainmore clearly defined in the blurred image frame provided in block 545than the scene information.

In one embodiment, 32 or more image frames are accumulated and averagedin blocks 535 and 540. However, any desired number of image frames maybe used in other embodiments, but with generally decreasing correctionaccuracy as frame count is decreased.

Referring now to the defocus-based approach, in block 530, a defocusoperation may be performed to intentionally defocus the image framescaptured by infrared sensors 132. For example, in one embodiment, one ormore actuators 199 may be used to adjust, move, or otherwise translateoptical element 180, infrared sensor assembly 128, and/or othercomponents of infrared imaging module 100 to cause infrared sensors 132to capture a blurred (e.g., unfocused) image frame of the scene. Othernon-actuator based techniques are also contemplated for intentionallydefocusing infrared image frames such as, for example, manual (e.g.,user-initiated) defocusing.

Although the scene may appear blurred in the image frame, FPN (e.g.,caused by one or more components of infrared imaging module 100) willremain unaffected by the defocusing operation. As a result, a blurredimage frame of the scene will be provided (block 545) with FPN remainingmore clearly defined in the blurred image than the scene information.

In the above discussion, the defocus-based approach has been describedwith regard to a single captured image frame. In another embodiment, thedefocus-based approach may include accumulating multiple image frameswhile the infrared imaging module 100 has been defocused and averagingthe defocused image frames to remove the effects of temporal noise andprovide a blurred image frame in block 545.

Thus, it will be appreciated that a blurred image frame may be providedin block 545 by either the motion-based approach or the defocus-basedapproach. Because much of the scene information will be blurred byeither motion, defocusing, or both, the blurred image frame may beeffectively considered a low pass filtered version of the originalcaptured image frames with respect to scene information.

In block 550, the blurred image frame is processed to determine updatedrow and column FPN terms (e.g., if row and column FPN terms have notbeen previously determined then the updated row and column FPN terms maybe new row and column FPN terms in the first iteration of block 550). Asused in this disclosure, the terms row and column may be usedinterchangeably depending on the orientation of infrared sensors 132and/or other components of infrared imaging module 100.

In one embodiment, block 550 includes determining a spatial FPNcorrection term for each row of the blurred image frame (e.g., each rowmay have its own spatial FPN correction term), and also determining aspatial FPN correction term for each column of the blurred image frame(e.g., each column may have its own spatial FPN correction term). Suchprocessing may be used to reduce the spatial and slowly varying (1/f)row and column FPN inherent in thermal imagers caused by, for example,1/f noise characteristics of amplifiers in ROIC 402 which may manifestas vertical and horizontal stripes in image frames.

Advantageously, by determining spatial row and column FPN terms usingthe blurred image frame, there will be a reduced risk of vertical andhorizontal objects in the actual imaged scene from being mistaken forrow and column noise (e.g., real scene content will be blurred while FPNremains unblurred).

In one embodiment, row and column FPN terms may be determined byconsidering differences between neighboring pixels of the blurred imageframe. For example, FIG. 6 illustrates differences between neighboringpixels in accordance with an embodiment of the disclosure. Specifically,in FIG. 6 a pixel 610 is compared to its 8 nearest horizontal neighbors:d0-d3 on one side and d4-d7 on the other side. Differences between theneighbor pixels can be averaged to obtain an estimate of the offseterror of the illustrated group of pixels. An offset error may becalculated for each pixel in a row or column and the average result maybe used to correct the entire row or column.

To prevent real scene data from being interpreted as noise, upper andlower threshold values may be used (thPix and −thPix). Pixel valuesfalling outside these threshold values (pixels d1 and d4 in thisexample) are not used to obtain the offset error. In addition, themaximum amount of row and column FPN correction may be limited by thesethreshold values.

Further techniques for performing spatial row and column FPN correctionprocessing are set forth in U.S. patent application Ser. No. 12/396,340filed Mar. 2, 2009 which is incorporated herein by reference in itsentirety.

Referring again to FIG. 5, the updated row and column FPN termsdetermined in block 550 are stored (block 552) and applied (block 555)to the blurred image frame provided in block 545. After these terms areapplied, some of the spatial row and column FPN in the blurred imageframe may be reduced. However, because such terms are applied generallyto rows and columns, additional FPN may remain such as spatiallyuncorrelated FPN associated with pixel to pixel drift or other causes.Neighborhoods of spatially correlated FPN may also remain which may notbe directly associated with individual rows and columns. Accordingly,further processing may be performed as discussed below to determine NUCterms.

In block 560, local contrast values (e.g., edges or absolute values ofgradients between adjacent or small groups of pixels) in the blurredimage frame are determined. If scene information in the blurred imageframe includes contrasting areas that have not been significantlyblurred (e.g., high contrast edges in the original scene data), thensuch features may be identified by a contrast determination process inblock 560.

For example, local contrast values in the blurred image frame may becalculated, or any other desired type of edge detection process may beapplied to identify certain pixels in the blurred image as being part ofan area of local contrast. Pixels that are marked in this manner may beconsidered as containing excessive high spatial frequency sceneinformation that would be interpreted as FPN (e.g., such regions maycorrespond to portions of the scene that have not been sufficientlyblurred). As such, these pixels may be excluded from being used in thefurther determination of NUC terms. In one embodiment, such contrastdetection processing may rely on a threshold that is higher than theexpected contrast value associated with FPN (e.g., pixels exhibiting acontrast value higher than the threshold may be considered to be sceneinformation, and those lower than the threshold may be considered to beexhibiting FPN).

In one embodiment, the contrast determination of block 560 may beperformed on the blurred image frame after row and column FPN terms havebeen applied to the blurred image frame (e.g., as shown in FIG. 5). Inanother embodiment, block 560 may be performed prior to block 550 todetermine contrast before row and column FPN terms are determined (e.g.,to prevent scene based contrast from contributing to the determinationof such terms).

Following block 560, it is expected that any high spatial frequencycontent remaining in the blurred image frame may be generally attributedto spatially uncorrelated FPN. In this regard, following block 560, muchof the other noise or actual desired scene based information has beenremoved or excluded from the blurred image frame due to: intentionalblurring of the image frame (e.g., by motion or defocusing in blocks 520through 545), application of row and column FPN terms (block 555), andcontrast determination (block 560).

Thus, it can be expected that following block 560, any remaining highspatial frequency content (e.g., exhibited as areas of contrast ordifferences in the blurred image frame) may be attributed to spatiallyuncorrelated FPN. Accordingly, in block 565, the blurred image frame ishigh pass filtered. In one embodiment, this may include applying a highpass filter to extract the high spatial frequency content from theblurred image frame. In another embodiment, this may include applying alow pass filter to the blurred image frame and taking a differencebetween the low pass filtered image frame and the unfiltered blurredimage frame to obtain the high spatial frequency content. In accordancewith various embodiments of the present disclosure, a high pass filtermay be implemented by calculating a mean difference between a sensorsignal (e.g., a pixel value) and its neighbors.

In block 570, a flat field correction process is performed on the highpass filtered blurred image frame to determine updated NUC terms (e.g.,if a NUC process has not previously been performed then the updated NUCterms may be new NUC terms in the first iteration of block 570).

For example, FIG. 7 illustrates a flat field correction technique 700 inaccordance with an embodiment of the disclosure. In FIG. 7, a NUC termmay be determined for each pixel 710 of the blurred image frame usingthe values of its neighboring pixels 712 to 726. For each pixel 710,several gradients may be determined based on the absolute differencebetween the values of various adjacent pixels. For example, absolutevalue differences may be determined between: pixels 712 and 714 (a leftto right diagonal gradient), pixels 716 and 718 (a top to bottomvertical gradient), pixels 720 and 722 (a right to left diagonalgradient), and pixels 724 and 726 (a left to right horizontal gradient).

These absolute differences may be summed to provide a summed gradientfor pixel 710. A weight value may be determined for pixel 710 that isinversely proportional to the summed gradient. This process may beperformed for all pixels 710 of the blurred image frame until a weightvalue is provided for each pixel 710. For areas with low gradients(e.g., areas that are blurry or have low contrast), the weight valuewill be close to one. Conversely, for areas with high gradients, theweight value will be zero or close to zero. The update to the NUC termas estimated by the high pass filter is multiplied with the weightvalue.

In one embodiment, the risk of introducing scene information into theNUC terms can be further reduced by applying some amount of temporaldamping to the NUC term determination process. For example, a temporaldamping factor X between 0 and 1 may be chosen such that the new NUCterm (NUC_(NEW)) stored is a weighted average of the old NUC term(NUC_(OLD)) and the estimated updated NUC term (NUC_(UPDATE)). In oneembodiment, this can be expressed asNUC_(NEW)=λ·NUC_(OLD)+(1−λ)·(NUC_(OLD)+NUC_(UPDATE)).

Although the determination of NUC terms has been described with regardto gradients, local contrast values may be used instead whereappropriate. Other techniques may also be used such as, for example,standard deviation calculations. Other types flat field correctionprocesses may be performed to determine NUC terms including, forexample, various processes identified in U.S. Pat. No. 6,028,309 issuedFeb. 22, 2000, U.S. Pat. No. 6,812,465 issued Nov. 2, 2004, and U.S.patent application Ser. No. 12/114,865 filed May 5, 2008, which areincorporated herein by reference in their entirety.

Referring again to FIG. 5, block 570 may include additional processingof the NUC terms. For example, in one embodiment, to preserve the scenesignal mean, the sum of all NUC terms may be normalized to zero bysubtracting the NUC term mean from each NUC term. Also in block 570, toavoid row and column noise from affecting the NUC terms, the mean valueof each row and column may be subtracted from the NUC terms for each rowand column. As a result, row and column FPN filters using the row andcolumn FPN terms determined in block 550 may be better able to filterout row and column noise in further iterations (e.g., as further shownin FIG. 8) after the NUC terms are applied to captured images (e.g., inblock 580 further discussed herein). In this regard, the row and columnFPN filters may in general use more data to calculate the per row andper column offset coefficients (e.g., row and column FPN terms) and maythus provide a more robust alternative for reducing spatially correlatedFPN than the NUC terms which are based on high pass filtering to capturespatially uncorrelated noise.

In blocks 571-573, additional high pass filtering and furtherdeterminations of updated NUC terms may be optionally performed toremove spatially correlated FPN with lower spatial frequency thanpreviously removed by row and column FPN terms. In this regard, somevariability in infrared sensors 132 or other components of infraredimaging module 100 may result in spatially correlated FPN noise thatcannot be easily modeled as row or column noise. Such spatiallycorrelated FPN may include, for example, window defects on a sensorpackage or a cluster of infrared sensors 132 that respond differently toirradiance than neighboring infrared sensors 132. In one embodiment,such spatially correlated FPN may be mitigated with an offsetcorrection. If the amount of such spatially correlated FPN issignificant, then the noise may also be detectable in the blurred imageframe. Since this type of noise may affect a neighborhood of pixels, ahigh pass filter with a small kernel may not detect the FPN in theneighborhood (e.g., all values used in high pass filter may be takenfrom the neighborhood of affected pixels and thus may be affected by thesame offset error). For example, if the high pass filtering of block 565is performed with a small kernel (e.g., considering only immediatelyadjacent pixels that fall within a neighborhood of pixels affected byspatially correlated FPN), then broadly distributed spatially correlatedFPN may not be detected.

For example, FIG. 11 illustrates spatially correlated FPN in aneighborhood of pixels in accordance with an embodiment of thedisclosure. As shown in a sample image frame 1100, a neighborhood ofpixels 1110 may exhibit spatially correlated FPN that is not preciselycorrelated to individual rows and columns and is distributed over aneighborhood of several pixels (e.g., a neighborhood of approximately 4by 4 pixels in this example). Sample image frame 1100 also includes aset of pixels 1120 exhibiting substantially uniform response that arenot used in filtering calculations, and a set of pixels 1130 that areused to estimate a low pass value for the neighborhood of pixels 1110.In one embodiment, pixels 1130 may be a number of pixels divisible bytwo in order to facilitate efficient hardware or software calculations.

Referring again to FIG. 5, in blocks 571-573, additional high passfiltering and further determinations of updated NUC terms may beoptionally performed to remove spatially correlated FPN such asexhibited by pixels 1110. In block 571, the updated NUC terms determinedin block 570 are applied to the blurred image frame. Thus, at this time,the blurred image frame will have been initially corrected for spatiallycorrelated FPN (e.g., by application of the updated row and column FPNterms in block 555), and also initially corrected for spatiallyuncorrelated FPN (e.g., by application of the updated NUC terms appliedin block 571).

In block 572, a further high pass filter is applied with a larger kernelthan was used in block 565, and further updated NUC terms may bedetermined in block 573. For example, to detect the spatially correlatedFPN present in pixels 1110, the high pass filter applied in block 572may include data from a sufficiently large enough neighborhood of pixelssuch that differences can be determined between unaffected pixels (e.g.,pixels 1120) and affected pixels (e.g., pixels 1110). For example, a lowpass filter with a large kernel can be used (e.g., an N by N kernel thatis much greater than 3 by 3 pixels) and the results may be subtracted toperform appropriate high pass filtering.

In one embodiment, for computational efficiency, a sparse kernel may beused such that only a small number of neighboring pixels inside an N byN neighborhood are used. For any given high pass filter operation usingdistant neighbors (e.g., a large kernel), there is a risk of modelingactual (potentially blurred) scene information as spatially correlatedFPN. Accordingly, in one embodiment, the temporal damping factor X maybe set close to 1 for updated NUC terms determined in block 573.

In various embodiments, blocks 571-573 may be repeated (e.g., cascaded)to iteratively perform high pass filtering with increasing kernel sizesto provide further updated NUC terms further correct for spatiallycorrelated FPN of desired neighborhood sizes. In one embodiment, thedecision to perform such iterations may be determined by whetherspatially correlated FPN has actually been removed by the updated NUCterms of the previous performance of blocks 571-573.

After blocks 571-573 are finished, a decision is made regarding whetherto apply the updated NUC terms to captured image frames (block 574). Forexample, if an average of the absolute value of the NUC terms for theentire image frame is less than a minimum threshold value, or greaterthan a maximum threshold value, the NUC terms may be deemed spurious orunlikely to provide meaningful correction. Alternatively, thresholdingcriteria may be applied to individual pixels to determine which pixelsreceive updated NUC terms. In one embodiment, the threshold values maycorrespond to differences between the newly calculated NUC terms andpreviously calculated NUC terms. In another embodiment, the thresholdvalues may be independent of previously calculated NUC terms. Othertests may be applied (e.g., spatial correlation tests) to determinewhether the NUC terms should be applied.

If the NUC terms are deemed spurious or unlikely to provide meaningfulcorrection, then the flow diagram returns to block 505. Otherwise, thenewly determined NUC terms are stored (block 575) to replace previousNUC terms (e.g., determined by a previously performed iteration of FIG.5) and applied (block 580) to captured image frames.

FIG. 8 illustrates various image processing techniques of FIG. 5 andother operations applied in an image processing pipeline 800 inaccordance with an embodiment of the disclosure. In this regard,pipeline 800 identifies various operations of FIG. 5 in the context ofan overall iterative image processing scheme for correcting image framesprovided by infrared imaging module 100. In some embodiments, pipeline800 may be provided by processing module 160 or processor 195 (both alsogenerally referred to as a processor) operating on image frames capturedby infrared sensors 132.

Image frames captured by infrared sensors 132 may be provided to a frameaverager 804 that integrates multiple image frames to provide imageframes 802 with an improved signal to noise ratio. Frame averager 804may be effectively provided by infrared sensors 132, ROIC 402, and othercomponents of infrared sensor assembly 128 that are implemented tosupport high image capture rates. For example, in one embodiment,infrared sensor assembly 128 may capture infrared image frames at aframe rate of 240 Hz (e.g., 240 images per second). In this embodiment,such a high frame rate may be implemented, for example, by operatinginfrared sensor assembly 128 at relatively low voltages (e.g.,compatible with mobile telephone voltages) and by using a relativelysmall array of infrared sensors 132 (e.g., an array of 64 by 64 infraredsensors in one embodiment).

In one embodiment, such infrared image frames may be provided frominfrared sensor assembly 128 to processing module 160 at a high framerate (e.g., 240 Hz or other frame rates). In another embodiment,infrared sensor assembly 128 may integrate over longer time periods, ormultiple time periods, to provide integrated (e.g., averaged) infraredimage frames to processing module 160 at a lower frame rate (e.g., 30Hz, 9 Hz, or other frame rates). Further information regardingimplementations that may be used to provide high image capture rates maybe found in U.S. Provisional Patent Application No. 61/495,879previously referenced herein.

Image frames 802 proceed through pipeline 800 where they are adjusted byvarious terms, temporally filtered, used to determine the variousadjustment terms, and gain compensated.

In blocks 810 and 814, factory gain terms 812 and factory offset terms816 are applied to image frames 802 to compensate for gain and offsetdifferences, respectively, between the various infrared sensors 132and/or other components of infrared imaging module 100 determined duringmanufacturing and testing.

In block 580, NUC terms 817 are applied to image frames 802 to correctfor FPN as discussed. In one embodiment, if NUC terms 817 have not yetbeen determined (e.g., before a NUC process has been initiated), thenblock 580 may not be performed or initialization values may be used forNUC terms 817 that result in no alteration to the image data (e.g.,offsets for every pixel would be equal to zero).

In blocks 818 and 822, column FPN terms 820 and row FPN terms 824,respectively, are applied to image frames 802. Column FPN terms 820 androw FPN terms 824 may be determined in accordance with block 550 asdiscussed. In one embodiment, if the column FPN terms 820 and row FPNterms 824 have not yet been determined (e.g., before a NUC process hasbeen initiated), then blocks 818 and 822 may not be performed orinitialization values may be used for the column FPN terms 820 and rowFPN terms 824 that result in no alteration to the image data (e.g.,offsets for every pixel would be equal to zero).

In block 826, temporal filtering is performed on image frames 802 inaccordance with a temporal noise reduction (TNR) process. FIG. 9illustrates a TNR process in accordance with an embodiment of thedisclosure. In FIG. 9, a presently received image frame 802 a and apreviously temporally filtered image frame 802 b are processed todetermine a new temporally filtered image frame 802 e. Image frames 802a and 802 b include local neighborhoods of pixels 803 a and 803 bcentered around pixels 805 a and 805 b, respectively. Neighborhoods 803a and 803 b correspond to the same locations within image frames 802 aand 802 b and are subsets of the total pixels in image frames 802 a and802 b. In the illustrated embodiment, neighborhoods 803 a and 803 binclude areas of 5 by 5 pixels. Other neighborhood sizes may be used inother embodiments.

Differences between corresponding pixels of neighborhoods 803 a and 803b are determined and averaged to provide an averaged delta value 805 cfor the location corresponding to pixels 805 a and 805 b. Averaged deltavalue 805 c may be used to determine weight values in block 807 to beapplied to pixels 805 a and 805 b of image frames 802 a and 802 b.

In one embodiment, as shown in graph 809, the weight values determinedin block 807 may be inversely proportional to averaged delta value 805 csuch that weight values drop rapidly towards zero when there are largedifferences between neighborhoods 803 a and 803 b. In this regard, largedifferences between neighborhoods 803 a and 803 b may indicate thatchanges have occurred within the scene (e.g., due to motion) and pixels802 a and 802 b may be appropriately weighted, in one embodiment, toavoid introducing blur across frame-to-frame scene changes. Otherassociations between weight values and averaged delta value 805 e may beused in various embodiments.

The weight values determined in block 807 may be applied to pixels 805 aand 805 b to determine a value for corresponding pixel 805 e of imageframe 802 e (block 811). In this regard, pixel 805 e may have a valuethat is a weighted average (or other combination) of pixels 805 a and805 b, depending on averaged delta value 805 c and the weight valuesdetermined in block 807.

For example, pixel 805 e of temporally filtered image frame 802 e may bea weighted sum of pixels 805 a and 805 b of image frames 802 a and 802b. If the average difference between pixels 805 a and 805 b is due tonoise, then it may be expected that the average change betweenneighborhoods 805 a and 805 b will be close to zero (e.g., correspondingto the average of uncorrelated changes). Under such circumstances, itmay be expected that the sum of the differences between neighborhoods805 a and 805 b will be close to zero. In this case, pixel 805 a ofimage frame 802 a may both be appropriately weighted so as to contributeto the value of pixel 805 e.

However, if the sum of such differences is not zero (e.g., evendiffering from zero by a small amount in one embodiment), then thechanges may be interpreted as being attributed to motion instead ofnoise. Thus, motion may be detected based on the average changeexhibited by neighborhoods 805 a and 805 b. Under these circumstances,pixel 805 a of image frame 802 a may be weighted heavily, while pixel805 b of image frame 802 b may be weighted lightly.

Other embodiments are also contemplated. For example, although averageddelta value 805 c has been described as being determined based onneighborhoods 805 a and 805 b, in other embodiments averaged delta value805 c may be determined based on any desired criteria (e.g., based onindividual pixels or other types of groups of sets of pixels).

In the above embodiments, image frame 802 a has been described as apresently received image frame and image frame 802 b has been describedas a previously temporally filtered image frame. In another embodiment,image frames 802 a and 802 b may be first and second image framescaptured by infrared imaging module 100 that have not been temporallyfiltered.

FIG. 10 illustrates further implementation details in relation to theTNR process of block 826. As shown in FIG. 10, image frames 802 a and802 b may be read into line buffers 1010 a and 1010 b, respectively, andimage frame 802 b (e.g., the previous image frame) may be stored in aframe buffer 1020 before being read into line buffer 1010 b. In oneembodiment, line buffers 1010 a-b and frame buffer 1020 may beimplemented by a block of random access memory (RAM) provided by anyappropriate component of infrared imaging module 100 and/or host device102.

Referring again to FIG. 8, image frame 802 e may be passed to anautomatic gain compensation block 828 for further processing to providea result image frame 830 that may be used by host device 102 as desired.

FIG. 8 further illustrates various operations that may be performed todetermine row and column FPN terms and NUC terms as discussed. In oneembodiment, these operations may use image frames 802 e as shown in FIG.8. Because image frames 802 e have already been temporally filtered, atleast some temporal noise may be removed and thus will not inadvertentlyaffect the determination of row and column FPN terms 824 and 820 and NUCterms 817. In another embodiment, non-temporally filtered image frames802 may be used.

In FIG. 8, blocks 510, 515, and 520 of FIG. 5 are collectivelyrepresented together. As discussed, a NUC process may be selectivelyinitiated and performed in response to various NUC process initiatingevents and based on various criteria or conditions. As also discussed,the NUC process may be performed in accordance with a motion-basedapproach (blocks 525, 535, and 540) or a defocus-based approach (block530) to provide a blurred image frame (block 545). FIG. 8 furtherillustrates various additional blocks 550, 552, 555, 560, 565, 570, 571,572, 573, and 575 previously discussed with regard to FIG. 5.

As shown in FIG. 8, row and column FPN terms 824 and 820 and NUC terms817 may be determined and applied in an iterative fashion such thatupdated terms are determined using image frames 802 to which previousterms have already been applied. As a result, the overall process ofFIG. 8 may repeatedly update and apply such terms to continuously reducethe noise in image frames 830 to be used by host device 102.

Referring again to FIG. 10, further implementation details areillustrated for various blocks of FIGS. 5 and 8 in relation to pipeline800. For example, blocks 525, 535, and 540 are shown as operating at thenormal frame rate of image frames 802 received by pipeline 800. In theembodiment shown in FIG. 10, the determination made in block 525 isrepresented as a decision diamond used to determine whether a givenimage frame 802 has sufficiently changed such that it may be consideredan image frame that will enhance the blur if added to other image framesand is therefore accumulated (block 535 is represented by an arrow inthis embodiment) and averaged (block 540).

Also in FIG. 10, the determination of column FPN terms 820 (block 550)is shown as operating at an update rate that in this example is 1/32 ofthe sensor frame rate (e.g., normal frame rate) due to the averagingperformed in block 540. Other update rates may be used in otherembodiments. Although only column FPN terms 820 are identified in FIG.10, row FPN terms 824 may be implemented in a similar fashion at thereduced frame rate.

FIG. 10 also illustrates further implementation details in relation tothe NUC determination process of block 570. In this regard, the blurredimage frame may be read to a line buffer 1030 (e.g., implemented by ablock of RAM provided by any appropriate component of infrared imagingmodule 100 and/or host device 102). The flat field correction technique700 of FIG. 7 may be performed on the blurred image frame.

In view of the present disclosure, it will be appreciated thattechniques described herein may be used to remove various types of FPN(e.g., including very high amplitude FPN) such as spatially correlatedrow and column FPN and spatially uncorrelated FPN.

Other embodiments are also contemplated. For example, in one embodiment,the rate at which row and column FPN terms and/or NUC terms are updatedcan be inversely proportional to the estimated amount of blur in theblurred image frame and/or inversely proportional to the magnitude oflocal contrast values (e.g., determined in block 560).

In various embodiments, the described techniques may provide advantagesover conventional shutter-based noise correction techniques. Forexample, by using a shutterless process, a shutter (e.g., such asshutter 105) need not be provided, thus permitting reductions in size,weight, cost, and mechanical complexity. Power and maximum voltagesupplied to, or generated by, infrared imaging module 100 may also bereduced if a shutter does not need to be mechanically operated.Reliability will be improved by removing the shutter as a potentialpoint of failure. A shutterless process also eliminates potential imageinterruption caused by the temporary blockage of the imaged scene by ashutter.

Also, by correcting for noise using intentionally blurred image framescaptured from a real world scene (not a uniform scene provided by ashutter), noise correction may be performed on image frames that haveirradiance levels similar to those of the actual scene desired to beimaged. This can improve the accuracy and effectiveness of noisecorrection terms determined in accordance with the various describedtechniques.

As discussed, in various embodiments, infrared imaging module 100 may beconfigured to operate at low voltage levels. In particular, infraredimaging module 100 may be implemented with circuitry configured tooperate at low power and/or in accordance with other parameters thatpermit infrared imaging module 100 to be conveniently and effectivelyimplemented in various types of host devices 102, such as mobile devicesand other devices.

For example, FIG. 12 illustrates a block diagram of anotherimplementation of infrared sensor assembly 128 including infraredsensors 132 and an LDO 1220 in accordance with an embodiment of thedisclosure. As shown, FIG. 12 also illustrates various components 1202,1204, 1205, 1206, 1208, and 1210 which may implemented in the same orsimilar manner as corresponding components previously described withregard to FIG. 4. FIG. 12 also illustrates bias correction circuitry1212 which may be used to adjust one or more bias voltages provided toinfrared sensors 132 (e.g., to compensate for temperature changes,self-heating, and/or other factors).

In some embodiments, LDO 1220 may be provided as part of infrared sensorassembly 128 (e.g., on the same chip and/or wafer level package as theROIC). For example, LDO 1220 may be provided as part of an FPA withinfrared sensor assembly 128. As discussed, such implementations mayreduce power supply noise introduced to infrared sensor assembly 128 andthus provide an improved PSRR. In addition, by implementing the LDO withthe ROIC, less die area may be consumed and fewer discrete die (orchips) are needed.

LDO 1220 receives an input voltage provided by a power source 1230 overa supply line 1232. LDO 1220 provides an output voltage to variouscomponents of infrared sensor assembly 128 over supply lines 1222. Inthis regard, LDO 1220 may provide substantially identical regulatedoutput voltages to various components of infrared sensor assembly 128 inresponse to a single input voltage received from power source 1230.

For example, in some embodiments, power source 1230 may provide an inputvoltage in a range of approximately 2.8 volts to approximately 11 volts(e.g., approximately 2.8 volts in one embodiment), and LDO 1220 mayprovide an output voltage in a range of approximately 1.5 volts toapproximately 2.8 volts (e.g., approximately 2.5 volts in oneembodiment). In this regard, LDO 1220 may be used to provide aconsistent regulated output voltage, regardless of whether power source1230 is implemented with a conventional voltage range of approximately 9volts to approximately 11 volts, or a low voltage such as approximately2.8 volts. As such, although various voltage ranges are provided for theinput and output voltages, it is contemplated that the output voltage ofLDO 1220 will remain fixed despite changes in the input voltage.

The implementation of LDO 1220 as part of infrared sensor assembly 128provides various advantages over conventional power implementations forFPAs. For example, conventional FPAs typically rely on multiple powersources, each of which may be provided separately to the FPA, andseparately distributed to the various components of the FPA. Byregulating a single power source 1230 by LDO 1220, appropriate voltagesmay be separately provided (e.g., to reduce possible noise) to allcomponents of infrared sensor assembly 128 with reduced complexity. Theuse of LDO 1220 also allows infrared sensor assembly 128 to operate in aconsistent manner, even if the input voltage from power source 1230changes (e.g., if the input voltage increases or decreases as a resultof charging or discharging a battery or other type of device used forpower source 1230).

The various components of infrared sensor assembly 128 shown in FIG. 12may also be implemented to operate at lower voltages than conventionaldevices. For example, as discussed, LDO 1220 may be implemented toprovide a low voltage (e.g., approximately 2.5 volts). This contrastswith the multiple higher voltages typically used to power conventionalFPAs, such as: approximately 3.3 volts to approximately 5 volts used topower digital circuitry; approximately 3.3 volts used to power analogcircuitry; and approximately 9 volts to approximately 11 volts used topower loads. Also, in some embodiments, the use of LDO 1220 may reduceor eliminate the need for a separate negative reference voltage to beprovided to infrared sensor assembly 128.

Additional aspects of the low voltage operation of infrared sensorassembly 128 may be further understood with reference to FIG. 13. FIG.13 illustrates a circuit diagram of a portion of infrared sensorassembly 128 of FIG. 12 in accordance with an embodiment of thedisclosure. In particular, FIG. 13 illustrates additional components ofbias correction circuitry 1212 (e.g., components 1326, 1330, 1332, 1334,1336, 1338, and 1341) connected to LDO 1220 and infrared sensors 132.For example, bias correction circuitry 1212 may be used to compensatefor temperature-dependent changes in bias voltages in accordance with anembodiment of the present disclosure. The operation of such additionalcomponents may be further understood with reference to similarcomponents identified in U.S. Pat. No. 7,679,048 issued Mar. 16, 2010which is hereby incorporated by reference in its entirety. Infraredsensor assembly 128 may also be implemented in accordance with thevarious components identified in U.S. Pat. No. 6,812,465 issued Nov. 2,2004 which is hereby incorporated by reference in its entirety.

In various embodiments, some or all of the bias correction circuitry1212 may be implemented on a global array basis as shown in FIG. 13(e.g., used for all infrared sensors 132 collectively in an array). Inother embodiments, some or all of the bias correction circuitry 1212 maybe implemented an individual sensor basis (e.g., entirely or partiallyduplicated for each infrared sensor 132). In some embodiments, biascorrection circuitry 1212 and other components of FIG. 13 may beimplemented as part of ROIC 1202.

As shown in FIG. 13, LDO 1220 provides a load voltage Vload to biascorrection circuitry 1212 along one of supply lines 1222. As discussed,in some embodiments, Vload may be approximately 2.5 volts whichcontrasts with larger voltages of approximately 9 volts to approximately11 volts that may be used as load voltages in conventional infraredimaging devices.

Based on Vload, bias correction circuitry 1212 provides a sensor biasvoltage Vbolo at a node 1360. Vbolo may be distributed to one or moreinfrared sensors 132 through appropriate switching circuitry 1370 (e.g.,represented by broken lines in FIG. 13). In some examples, switchingcircuitry 1370 may be implemented in accordance with appropriatecomponents identified in U.S. Pat. Nos. 6,812,465 and 7,679,048previously referenced herein.

Each infrared sensor 132 includes a node 1350 which receives Vbolothrough switching circuitry 1370, and another node 1352 which may beconnected to ground, a substrate, and/or a negative reference voltage.In some embodiments, the voltage at node 1360 may be substantially thesame as Vbolo provided at nodes 1350. In other embodiments, the voltageat node 1360 may be adjusted to compensate for possible voltage dropsassociated with switching circuitry 1370 and/or other factors.

Vbolo may be implemented with lower voltages than are typically used forconventional infrared sensor biasing. In one embodiment, Vbolo may be ina range of approximately 0.2 volts to approximately 0.7 volts. Inanother embodiment, Vbolo may be in a range of approximately 0.4 voltsto approximately 0.6 volts. In another embodiment, Vbolo may beapproximately 0.5 volts, in contrast, conventional infrared sensorstypically use bias voltages of approximately 1 volt.

The use of a lower bias voltage for infrared sensors 132 in accordancewith the present disclosure permits infrared sensor assembly 128 toexhibit significantly reduced power consumption in comparison withconventional infrared imaging devices. In particular, the powerconsumption of each infrared sensor 132 is reduced by the square of thebias voltage. As a result, a reduction from, for example, 1.0 volt to0.5 volts provides a significant reduction in power, especially whenapplied to many infrared sensors 132 in an infrared sensor array. Thisreduction in power may also result in reduced self-heating of infraredsensor assembly 128.

In accordance with additional embodiments of the present disclosure,various techniques are provided for reducing the effects of noise inimage frames provided by infrared imaging devices operating at lowvoltages. In this regard, when infrared sensor assembly 128 is operatedwith low voltages as described, noise, self-heating, and/or otherphenomena may, if uncorrected, become more pronounced in image framesprovided by infrared sensor assembly 128.

For example, referring to FIG. 13, when LDO 1220 maintains Vload at alow voltage in the manner described herein, Vbolo will also bemaintained at its corresponding low voltage and the relative size of itsoutput signals may be reduced. As a result, noise, self-heating, and/orother phenomena may have a greater effect on the smaller output signalsread out from infrared sensors 132, resulting in variations (e.g.,errors) in the output signals. If uncorrected, these variations may beexhibited as noise in the image frames. Moreover, although low voltageoperation may reduce the overall amount of certain phenomena (e.g.,self-heating), the smaller output signals may permit the remaining errorsources (e.g., residual self-heating) to have a disproportionate effecton the output signals during low voltage operation.

To compensate for such phenomena, infrared sensor assembly 128, infraredimaging module 100, and/or host device 102 may be implemented withvarious array sizes, frame rates, and/or frame averaging techniques. Forexample, as discussed, a variety of different array sizes arecontemplated for infrared sensors 132. In some embodiments, infraredsensors 132 may be implemented with array sizes ranging from 32 by 32 to160 by 120 infrared sensors 132. Other example array sizes include 80 by64, 80 by 60, 64 by 64, and 64 by 32. Any desired array size may beused.

Advantageously, when implemented with such relatively small array sizes,infrared sensor assembly 128 may provide image frames at relatively highframe rates without requiring significant changes to ROIC and relatedcircuitry. For example, in some embodiments, frame rates may range fromapproximately 120 Hz to approximately 480 Hz.

In some embodiments, the array size and the frame rate may be scaledrelative to each other (e.g., in an inversely proportional manner orotherwise) such that larger arrays are implemented with lower framerates, and smaller arrays are implemented with higher frame rates. Forexample, in one embodiment, an array of 160 by 120 may provide a framerate of approximately 120 Hz. In another embodiment, an array of 80 by60 may provide a correspondingly higher frame rate of approximately 240Hz. Other frame rates are also contemplated.

By scaling the array size and the frame rate relative to each other, theparticular readout timing of rows and/or columns of the FPA array mayremain consistent, regardless of the actual FPA array size or framerate. In one embodiment, the readout timing may be approximately 63microseconds per row or column.

As previously discussed with regard to FIG. 8, the image frames capturedby infrared sensors 132 may be provided to a frame averager 804 thatintegrates multiple image frames to provide image frames 802 (e.g.,processed image frames) with a lower frame rate (e.g., approximately 30Hz, approximately 60 Hz, or other frame rates) and with an improvedsignal to noise ratio. In particular, by averaging the high frame rateimage frames provided by a relatively small FPA array, image noiseattributable to low voltage operation may be effectively averaged outand/or substantially reduced in image frames 802. Accordingly, infraredsensor assembly 128 may be operated at relatively low voltages providedby LDO 1220 as discussed without experiencing additional noise andrelated side effects in the resulting image frames 802 after processingby frame averager 804.

Other embodiments are also contemplated. For example, although a singlearray of infrared sensors 132 is illustrated, it is contemplated thatmultiple such arrays may be used together to provide higher resolutionimage frames (e.g., a scene may be imaged across multiple such arrays).Such arrays may be provided in multiple infrared sensor assemblies 128and/or provided in the same infrared sensor assembly 128. Each sucharray may be operated at low voltages as described, and also may beprovided with associated ROIC circuitry such that each array may stillbe operated at a relatively high frame rate. The high frame rate imageframes provided by such arrays may be averaged by shared or dedicatedframe averagers 804 to reduce and/or eliminate noise associated with lowvoltage operation. As a result, high resolution infrared images may beobtained while still operating at low voltages.

In various embodiments, infrared sensor assembly 128 may be implementedwith appropriate dimensions to permit infrared imaging module 100 to beused with a small form factor socket 104, such as a socket used formobile devices. For example, in some embodiments, infrared sensorassembly 128 may be implemented with a chip size in a range ofapproximately 4.0 mm by approximately 4.0 mm to approximately 5.5 mm byapproximately 5.5 mm (e.g., approximately 4.0 mm by approximately 5.5 mmin one example). Infrared sensor assembly 128 may be implemented withsuch sizes or other appropriate sizes to permit use with socket 104implemented with various sizes such as: 8.5 mm by 8.5 mm, 8.5 mm by 5.9mm, 6.0 mm by 6.0 mm, 5.5 mm by 5.5 mm, 4.5 mm by 4.5 mm, and/or othersocket sizes such as, for example, those identified in Table 1 of U.S.Provisional Patent Application No. 61/495,873 previously referencedherein.

One or more embodiments of the disclosure are directed to a measurementdevice that may be conveniently carried by electricians or other usersto work sites, and utilized by such users in performing measurements andinspections in an integrated manner without requiring users to usemultiple different devices. For example, electricians or other usersworking on an electrical installation job may use one or moreembodiments of the measurement device to precisely measure variousdistances or spans of electrical wire installation locations todetermine the length of wires required, inspect a wire spool to checkwhether there is a wire long enough remaining on the spool, and checkthe length of cut wires before installing them at the installationlocations. After installing the wires and/or other electricalcomponents, users may also use the measurement device to check variouselectrical parameters associated with the wires and/or other electricalcomponents to detect and/or diagnose electrical faults. In addition,electricians or other users may utilize the measurement device to view athermal image of a scene to conveniently locate and/or identifypotential electrical faults, for example.

Turning to FIGS. 14A-15, a measurement device 1400 (e.g., a measuringapparatus, meter, or instrument) according to various embodiments of thedisclosure will now be described. For example, measurement device 1400may be used by electricians and other persons to perform various taskswhile working in the field. Such tasks may include, for example,installing electrical systems, inspecting electrical systems, and/orother tasks in performing a series of electrical measurement,installation, and inspection tasks. One or more embodiments ofmeasurement device 1400 may beneficially aid such electricians and otherpersons by providing, in a convenient form factor, various integratedand cooperative measurement and inspection capabilities such as distancemeasurement, wire length measurement, electrical parameter measurement,and/or thermal imaging capabilities.

FIGS. 14A-14B illustrate various exterior views of measurement device1400 in accordance with embodiments of the disclosure. Morespecifically, FIG. 14A shows a front side view and FIG. 14B shows a topside view, respectively, of measurement device 1400. Various componentsof measurement device 1400 may be disposed in (e.g., completely enclosedwithin, substantially enclosed within, and/or partially enclosed within)and/or otherwise disposed on a housing 1402. Housing 1402 may be adaptedto be hand-held or otherwise conveniently handled by a user (e.g., anelectrician) when being carried or used, such as during field operation.As shown, housing 1402 in one embodiment may be of a size and shapegenerally similar to a conventional multimeter typically carried to awork site by an electrician. In another embodiment, housing 1402 mayinclude a handle or other protrusion (e.g., a pistol grip) that permitsa user to comfortably hold housing 1402. It should be noted, however,that housing 1402 may in general be of any size and/or shape adapted forcomfortable field use, and need not be limited to shapes that permitone-hand use.

In one embodiment, measurement device 1400 may include, disposed in oron housing 1402, a plurality of electrical terminals 1404 (e.g.,including one or more electrical terminals identified as 1404A-1404D),an optical emitter 1406, a sensor 1408, an infrared imaging module 1416,a display 1418, a user control 1422, and/or a display 1424. Thelocations of the various components illustrated in FIGS. 14A-14B areprovided only for purposes of exposition, and the various componentsidentified herein may be disposed in or on any other location on housing1402 as desired or suitable for particular applications of measurementdevice 1400. For example, in other embodiments, all or some of theplurality of terminals 1404 may be disposed on a side or bottom surfaceof housing 1404 if such locations are more convenient in the use and/ormanufacture of measurement device 1400. It will also be appreciated thatone or more components of measurement device 1400 may be combined witheach other and/or omitted as desired depending on particularapplications of measurement device 1400, without departing from thescope and spirit of the disclosure.

Referring now to FIG. 15, a block diagram of measurement device 1400 isillustrated in accordance with an embodiment of the disclosure.Measurement device 1400 may include a distance measurement circuit 1510,a length measurement circuit 1512, an electrical meter circuit 1514, amemory 1520, and/or additional components 1526. Distance measurementcircuit 1510, length measurement circuit 1512, and electrical metercircuit 1514 may be implemented with any appropriate combination ofanalog and/or digital circuits configured to perform various operationsdescribed herein.

In one embodiment, various measurement operations may be performed byanalog circuits. In another embodiment, some operations may be performedby analog circuits, with analog signals being converted to digitalsignals (e.g., using analog-to-digital converters (DACs) or othersampling techniques) for further processing by digital circuits. In yetanother embodiment, output from digital circuits may be converted backto analog signals (e.g., using digital-to-analog converters or DACs) foryet further processing.

In some embodiments, digital circuit portions of distance measurementcircuit 1510, length measurement circuit 1512, or electrical metercircuit 1514 may be implemented as application-specific integratedcircuits (ASICs) specifically configured to perform measurementoperations described herein with high performance and/or highefficiency. In other embodiments, digital circuit portions may beimplemented with a general purpose central processing unit (CPU), amicrocontroller, a digital signal processing (DSP) device, or otherprocessor, which may be configured to execute appropriate softwareinstructions to perform various operations described herein.

In some embodiments, distance measurement circuit 1510, lengthmeasurement circuit 1512, and electrical meter circuit 1514 may beimplemented in a single chip, module, packaging, or circuit board,and/or may share some common subcomponents. For example, distancemeasurement circuit 1510, length measurement circuit 1512, andelectrical meter circuit 1514 may all be provided in a single chip, andshare common subcomponents such as ADCs, DACs, or I/O logic. In anotherexample, a single general purpose processor may be utilized to implementdigital circuit portions of all three components, and may be configuredto selectively execute three different software modules each configuredto cause the processor to perform appropriate processing forcorresponding measurement operations. In other embodiments, at least oneof distance measurement circuit 1510, length measurement circuit 1512,and electrical meter circuit 1514 may be implemented in a chip, module,or packaging that is separate from the others.

Distance measurement circuit 1510 may be communicatively coupled (e.g.,connected via appropriate circuit board traces, buses, wires, cables,ribbon connectors, and/or other connections suitable for transmittinganalog and/or digital signals) to optical emitter 1406 and sensor 1408.Distance measurement circuit 1510 may be configured to determine adistance 1548 from measurement device 1400 to a target 1542 bytransmitting an optical beam using optical emitter 1406 and detecting,using sensor 1408, the optical beam reflected by target 1542. Forexample, FIG. 15 shows a path 1544 that may be taken by the transmittedoptical beam to target 1542 and a path 1546 that may be taken by thereflected optical beam back to sensor 1408. Optical beam may betransmitted as one or more pulses, a continuous beam, a beam that ismodulated to encode pulses, and/or other optical transmissions suitablefor determining distance 1546 based on the reflected optical beam fromthe target. In some embodiments, distance 1548 may be determined using aconventional time-of-flight distance calculation technique orphase-shift detection technique. Accordingly, distance measurementcircuit 1510 may include any suitable combination of analog and digitalcircuits, and/or any suitable combination of hardware and softwareconfigured to implement appropriate distance calculation techniques.Optical beams may be transmitted periodically or in response to a userinput (e.g., when user presses a button on user control 1422).

In one embodiment, optical emitter 1406 may be implemented using a laser(e.g., a laser diode) adapted to operate in response to an appropriatecontrol signal from distance measurement circuit 1510. In thisembodiment, sensor 1408 may be implemented using an optical detectorthat is sensitive to laser light in a band of wavelengths correspondingto that of the laser. In other embodiments, other optical light sourcesmay be used to implement optical emitter 1406, with sensor 1408 beingimplemented using optical detectors appropriate for the type of opticallight source being used. Such optical light sources may include, forexample, visible light sources; near, midrange, and/or far infraredlight sources; and/or other non-visible light sources. Accordingly,optical emitter 1406 may be implemented using a light emitter that maybe appropriate and/or desired for particular applications of measurementdevice 1400. Non-optical emitters and detectors are also contemplatedand within the scope and spirit of the disclosure. For example, insteadof an optical emitter and detector, an ultrasound emitter and acorresponding ultrasonic detector, which may be sufficient for shortrange distance measurement applications, may be utilized for distancemeasurement.

In one embodiment, optical emitter 1406 may be configured to transmit acontinuous optical beam while measurement device 1400 is being used fordistance measurement (e.g., put into a distance measurement mode). Sucha beam may produce a visible indication of where the optical pulseand/or beam would hit (e.g., a laser dot designating the point ofimpingement), thereby aiding a user in aiming the optical pulse and/orbeam on a desired target. In such an embodiment, the optical beam may beappropriately modulated or otherwise altered to encode optical pulses,amplitude modulations, frequency modulations, or other modulations ofthe optical beam. In another embodiment, a separate optical emitter maybe utilized to provide a visible indication of the point of impingement.

Length measurement circuit 1512 may be electrically coupled (e.g., usingcircuit board traces, cables, wires, and/or other appropriate electricalpaths with sufficient power ratings for desired applications ofmeasurement device 1400) to one or more of terminals 1404, andconfigured to determine an approximate length of a wire or cableelectrically connected thereto via the one or more of terminals 1404.Similarly, electrical meter circuit 1514 may be electrically coupled toone or more of terminals 1404, and configured to determine variouselectrical parameters (e.g., voltage, current, resistance, capacitance,or other parameters) of an external article (e.g., electrical/electronicdevices, components, circuit boards, wires, cables, traces, and/or otherelectrical/electronic articles) electrically connected thereto via theone or more of terminals 1404.

In this regard, in one or more embodiments terminals 1404 may be adaptedto form an electrical connection to external wires, cables, or otherarticles. For example, in one or more embodiments, terminals 1404 mayinclude appropriate connection mechanisms (e.g., receptacles, sockets,plugs, pins, clips, screws, or other suitable electrical/electronicconnectors) for electrically connecting to external wires, cables, orother articles. In one embodiment, terminals 1404 may include suitableconnection mechanisms configured to insertably and/or releasably receiveappropriate test leads 1530. In some embodiments, test leads 1530 mayinclude a standard plug or other type of connector at one end, and/or aclip (e.g., an alligator clip) or a probe at the other end. Test leads1530 having a proprietary design are also contemplated.

In one embodiment, each of terminals 1404 may be wired and configuredfor a specific type of input. For example, terminal 1404A may be used tomeasure voltage, terminal 1404B may be used to measure current, andterminal 1404D may be used to measure a wire length, with terminal 1404Cused to provide a ground connection. In another example, terminals 1404A1404D may be further differentiated based on voltage ranges, currentranges, resistance ranges, or other measurement ranges. In anotherembodiment, terminals 1404 may be switchable (e.g., by automatic sensingand/or receiving manual selection to adjust an appropriate switchingcircuit) to selectably receive different types of inputs. Thus, lengthmeasurement circuit 1512 and electrical meter circuit 1514 may beelectrically connected to an external article (e.g., external article1532) or a wire (e.g., wire 1534 on a spool) via one or more terminals1404. A test lead (e.g., test lead 1530) may be utilized to electricallyconnect to the external article or wire if desired.

Returning to description of length measurement circuit 1512, a length ofa wire (e.g., wire 1534) may be determined, in one embodiment, using atime-domain reflectometry (TDR) technique. More specifically, forexample, length measurement circuit 1512 may include an appropriateanalog circuit, digital circuit, and/or software module configured togenerate and transmit an electrical pulse (e.g., a voltage change havinga short rise time) from a connected end 1534A of wire 1534, to receivethe pulse reflected back from an open end 1534B of wire 1534, and todetermine the length of wire 1534 based on a total propagation time ofthe pulse. That is, the length may be determined from the timedifference between the transmission of the pulse and the receipt of thereflected pulse. Because the propagation speed of an electrical signalis constant for a given type of wire, the length of wire 1534 may becalculated from the time it takes for an electrical signal to travelfrom connected end 1534A to open end 1534B and back.

In this regard, length measurement circuit 1512 in one embodiment mayinclude a lookup table (e.g., in an appropriate data structure and/or ahardware memory device) associating various standardized wire gauges(e.g., American wire gauge (AWG) standard) with a correspondingpropagation speed therethrough. In this embodiment, a user may input orotherwise select (e.g., using user control 1422) a wire gauge value forthe wire to be measured. In another embodiment, length measurementcircuit 1512 may be configured to derive an appropriate propagationspeed to base the length calculation on, by measuring a totalpropagation time through a wire of a known length. For example, a usermay cut a small wire segment of a certain length from a spool of wire tobe measured, and connect the segment to measurement device 1400 to allowlength measurement circuit 1512 to automatically determine thepropagation speed. Such an embodiment may allow a user to measure alength of a wire when the gauge of the wire is not known or when thewire is of a non-standard gauge. In another embodiment, an appropriatepropagation speed for determining a length of the wire may be providedby a user (e.g., input using user control 1422), without a need for alookup table.

In one embodiment, length measurement circuit 1512 may include anappropriate analog circuit, digital circuit, and/or software moduleconfigured to determine an approximate length of a wire based on acumulative resistance through the length of the wire. Because aresistance through a wire is proportional to the length of the wire, anapproximate length may be calculated by high-precision measurement of acumulative resistance through the length of the wire. In this regard,length measurement circuit 1512 in one embodiment may include anotherlookup table associating various standardized wire gauges with a unitresistance value (e.g., milliohms per feet). In another embodiment,length measurement circuit 1512 may be configured to derive a unitresistance value by measuring the resistance of a wire of a known lengthsupplied by a user. In another embodiment, an appropriate unitresistance value for determining a length of the wire may be provided bya user (e.g., input using user control 1422), without a need for alookup table.

Electrical meter circuit 1514 may include an appropriate analog circuit,digital circuit, and/or software module to measure various electricalparameters such as voltage, current, resistance, capacitance, and/orother parameters associated with an external article connected thereto.For example, electrical meter circuit 1514 may be configured to generateand transmit through the external article a reference electrical signal(e.g., a reference voltage or a reference current), and to determine anelectrical parameter (e.g., a resistance) based on changes observed inthe electrical signal (e.g., a voltage drop). In various embodiments,electrical meter circuit 1514 may be configured to determine one or moreselected electrical parameters in response to a user selection at usercontrol 1422. In some embodiments, electrical meter circuit 1514 may beconfigured to provide auto-ranging and/or auto-sensing of electricalparameters.

Display 1418 may be communicatively coupled to distance measurementcircuit 1510, length measurement circuit 1512, and electrical metercircuit 1514. Display 1418 may be configured to present, indicate, orotherwise convey information indicative of the distance, the length,and/or the electrical parameters determined by the respective circuits.In this regard, display 1418 may include a display processor configuredto convert signals or data from the respective circuits into appropriateforms for presentation. The display processor may be implemented usingany appropriate combination of analog circuits, digital circuits, and/orsoftware modules. For example, in some embodiments, a general-purposemicrocontroller or a general-purpose processing core may be utilized asthe display processor. In other embodiments, dedicated hardware logic oran ASIC may be utilized to implement the display processor. In someembodiments, the display processor may not be implemented as part ofdisplay 1418, but rather as part of distance measurement circuit 1510,length measurement circuit 1512, electrical meter circuit 1514, and/orother portions of measurement device 1400.

In some embodiments, the display processor may be implemented as part ofa processor 1519 that is utilized to implement various circuits ofmeasurement device 1400. In addition to implementing the displayprocessor, processor 1519 may be adapted to implement processors fordistance measurement circuit 1510, length measurement circuit 1512,electrical meter circuit 1514, and/or other portions of measurementdevice 1400 as desired for particular embodiments.

In various embodiments, display 1418 may be implemented using analpha-numeric readout panel (e.g., a segmented LED panel, a vacuumfluorescent display (VFD) panel, a liquid crystal display (LCD) panel,or other multi-segment, multi-element, or dot-matrix panels) and/or anelectronic display screen (e.g., a cathode ray tube (CRT), a LCD screen,or other types of video displays and monitors). In some embodiments,display 1418 may be configured to display numbers, letters, and/orsymbols suitable for presenting the information generated by measurementdevice 1400. For example, display 1418 may be configured to display themeasured distance, length, and/or electrical parameters in numericaldigits, with appropriate letters or symbols displayed to indicate thetype of information (e.g., whether the numbers indicate a distance, wirelength, voltage, current, resistance, or capacitance, or otherparameter) and the applicable unit (e.g., meters, inches, feet, volts,amperes, ohms, farads, or other units). In other embodiments, display1418 may be configured to present, in addition to or instead of anumerical presentation, a graphical presentation of the informationgenerated by measurement device 1400. Such graphical presentation mayinclude, for example, bar graphs, pie graphs, dials, line graphs,images, graphics or other suitable presentation of correspondingmeasurement values. In yet another example, display 1418 may beimplemented using a pointer (e.g., a needle) moving over on a dialcalibrated for the various measurements that may be presented. It isalso contemplated that combinations of display implementations describedabove may be utilized for display 1418.

Memory 1520 may include one or more memory devices to store data andinformation, including the information indicative of the distancemeasurements, the length measurements, and the electrical parametermeasurements determined by the respective circuits. The one or morememory devices may include various types of memory including volatileand non-volatile memory devices, such as RAM (Random Access Memory),flash memory, EEPROM (Electrically-Erasable Read-Only Memory), ROM (ReadOnly Memory), a hard disk drive, other suitable memory devices. In someembodiments, memory 1520 may be configured to store softwareinstructions that may be accessed and executed by display processors ofdisplay 1418/1424, measurement circuit 1510, length measurement circuit1512, electrical meter circuit 1514, processor 1519, and/or othercomponents of measurement device 1400. In some embodiments, suchinstructions may also be stored in a computer-readable medium, such as acompact disc, a digital video disc, a flash drive, or other suitablemedium, for downloading or otherwise transferring such instructions tomeasurement device 1400.

In one or more embodiments, measurement device 1600 may include a logicdevice 1601 which encompasses one or more of electrical meter circuit1514, processor 1519, memory 1520, and/or additional measurementcomponents 1611. Logic device 1601 may, for example, be used todetermine one or more physical parameters associated with an externalarticle (e.g., in response to one or more signals received from sensorsand/or other components as appropriate) in accordance with any of thevarious techniques described herein. In some embodiments, logic device1601 may be implemented as described herein with regard to processingmodule 160 and/or processor 195.

In one embodiment, memory 1520 may be implemented as a separatecomponent communicatively coupled to other components of measurementdevice 1400. In other embodiments, memory 1520 may be implemented aspart of (e.g., embedded, distributed throughout, or otherwiseimplemented) measurement circuit 1510, length measurement circuit 1512,electrical meter circuit 1514, display 1418, processor 1519, and/orother components of measurement device 1400.

In some embodiments, measurement circuit 1510, length measurementcircuit 1512, electrical meter circuit 1514, display 1418, and/or othercomponents of measurement device 1400 may be configured to store inmemory 1520 the information indicative of the distance measurements, thelength measurements, and the electrical parameter measurementsdetermined by the respective circuits. The stored information may berecalled or otherwise accessed by various components of measurementdevice 1400. For example, in one embodiment, the display processor ofdisplay 1418 or processor 1519 may be configured to store in memory 1520one or more measurement values as determined by the measurementcircuits, and to access the previously stored measurement values so thatdisplay 1418 may present both current and previous measurements forconvenient comparison by a user. In other embodiments, measurementcircuit 1510, length measurement circuit 1512, electrical meter circuit1514, and/or other components of measurement device 1400 may beconfigured to perform the storing and recalling.

Thus, for example, when an electrician is installing an electrical wire,measurement device 1400 may beneficially allow the electrician toconveniently compare a previously obtained distance measurement of aninstallation location (e.g., the span or height of the installationlocation) with a currently measured length of a wire to be used for thelocation. The electrician may conveniently view the two differentmeasurements on display 1418, for example, to verify whether the wire islong enough for the location without having to separately write down ormemorize the span of the location. In some embodiments, one or morepreviously stored measurements (e.g., distance measurements) may bedisplayed simultaneously with a currently obtained measurement (e.g.,wire length measurements). In other embodiments, a user may be able toswitch or flip between (e.g., using a key or button provided by usercontrol 1422) the previous and current measurements to view them in analternating manner.

In some embodiments, the stored measurements and the currently obtainedmeasurements may be further managed or processed by distance measurementcircuit 1510, length measurement circuit 1512, electrical meter circuit1514, display 1418, and/or other components of measurement device 1400.In one embodiment, the display processor of display 1418 or othercomponents may be configured to obtain an aggregate value of two or moremeasurements, an average value of two or more measurements, or otherderivations from two or more values. Thus, for example, when multipledistance measurements are required for a wire installation location(e.g., when a wire installation has bends and turns rather than astraight-line connection), measurement device 1400 may beneficiallyprovide an electrician with an aggregate span (e.g., a sum of multipledistance measurements) of the installation location so that theelectrician does not have to write down and add up multiple measurementsto figure out how long a wire is needed.

In another embodiment, the display processor of display 1418 or othercomponents may be configured to compare the previously storedmeasurements with the currently obtained measurements. An alarm,message, or other notification may optionally be generated based on thecomparison. Thus, for example, measurement device 1400 may beneficiallyperform a comparison of a stored distance measurement and a currentlyobtained wire length measurement, and provide an electrician with anindication (e.g., through a beep, a flashing light, or othernotification tones and/or lights) of whether or not the wire is longenough for the distance. As such, measurement device 1400 may allow theelectrician to check whether there is enough wire left on a spool tocover an installation location without having to read and comparemeasured values on display 1418. In another example situation,measurement device 1400 may indicate whether or not a wire is cut to acorrect length by comparing a current measurement of the length of thewire to previously measured distances. As may be appreciated, thecomparison operations may be performed on aggregate values or otherderived values as well.

Infrared imaging module 1416 may be a small form factor infrared cameraor a small form factor infrared imaging device suitable for capturingthermal images. For example, infrared imaging module 1416 may beimplemented using infrared imaging module 100 of FIG. 1 or otherembodiments disclosed herein with respect to FIGS. 1-13. Infraredimaging module 1416 may include an FPA implemented, for example, inaccordance with various embodiments disclosed herein or others whereappropriate.

Infrared imaging module 1416 may be configured to capture, process,and/or otherwise manage infrared images (e.g., including thermal images)of a scene (e.g., a scene 1540) associated with an environment of auser. In this regard, infrared imaging module 1416 may be attached,mounted, installed, plugged in or otherwise disposed at any suitablelocation on or in housing 1402 to allow a desired portion of the user'senvironment to be placed within a field of view (FOV) 1541 of infraredimaging module 1416 when the user points measurement device 1400generally toward the desired portion of the user's environment. Also, asdiscussed above in connection with infrared imaging module 100 of FIG.1, infrared imaging module 1416 and/or associated components may beconfigured to perform various NUC processes described herein.

The captured thermal images of the scene may be presented asuser-viewable thermal images (e.g., thermograms) for viewing by theuser. In one embodiment, display 1418 (e.g., implemented using anelectronic display screen) may be configured to display theuser-viewable thermal images. In another embodiment, measurement device1400 may include another display 1424 fixed relative to the housing(e.g., attached thereto, disposed therein, disposed thereon, and/orotherwise fixed) and configured to display the user-viewable thermalimages. Display 1424 may be implemented with an electronic displayscreen, such as a LCD, a LED, a cathode ray tube (CRT), or other typesof generally known electronic displays suitable for showing imagesand/or videos. Although two displays 1418 and 1424 are shown in theexample of FIGS. 14 and 15, it is contemplated that any number of suchdisplays 1418/1424 may be included in measurement device 1400 dependingon desired applications of measurement device 1400.

According to various embodiments, infrared imaging module 1416,processor 1519, and/or display 1418/1424 may be configured to performsuitable conversion operations to generate the user-viewable thermalimages from the thermal images captured at an FPA of infrared imagingmodule. For example, the temperature data contained in the pixels of thethermal images may be converted into appropriate gray-scaled orcolor-scaled pixels to construct images that can be viewed by a person.In some embodiments, the user-viewable images may optionally include atemperature scale or legend that indicates the approximate temperatureof corresponding pixel color and/or intensity.

By viewing such user-viewable thermal images, a user may be able toperform various electrical inspections. For example, user-viewablethermal images may quickly reveal hot spots 1550A and/or cold spots1550B in electrical installations 1550, which may indicate failures suchas poor connections, corroded connections, incorrectly securedconnections, internal damage, unbalanced loads, and other variouselectrical faults. In another example, cold spots 1550B may indicatemoisture, which may be a cause for electrical failure. Thus, forexample, using infrared imaging module 1416 of measurement device 1400,an electrician working at an electrical installation location mayquickly scan the installation location after measuring and installing(e.g., utilizing measurement device 1400 as described above) electricalwires and components to inspect for any fault in the installation. Itshould be appreciated that the thermal images captured and presented bymeasurement device 1400 may also be utilized for various other purposes,such as inspecting and detecting water and gas leaks and otherapplications of thermal imaging.

In some embodiments, the user-viewable thermal images may provide visualguidance for aiming the optical beam transmitted from optical emitter1406 to measure distances. For example, in one embodiment, infraredimaging module 1416 may be positioned and oriented relative to opticalemitter 1406 such that the optical beam reflected off target 1542 may beplaced within FOV 1541 of infrared imaging module 1416. Further, in thisembodiment, infrared imaging module 1416 may be configured to besensitive to IR radiation generated by the optical beam. Alternatively,optical emitter 1406 may be configured to generate an optical beam in IRwavelengths which infrared imaging module 1416 may be sensitive to. Ineither implementation, infrared imaging module 1416 may capture thermalimages that include images of the reflected optical beam. Thus, byconveniently viewing the user-viewable images, a user may be able to aimthe optical beam from optical emitter 1406 toward a desired spot ortarget for distance measurement.

In another embodiment, infrared imaging module 1416, display 1418/1424,and/or processor 1519 may be configured to overlay onto theuser-viewable thermal images a reticle, a crosshair, or other marksuitable for indicating the impingement point of the optical beam fromoptical emitter 1406. Such a reticle or crosshair on the user-viewablescreens may provide an additional or alternative visual guidance inaiming the optical beam for distance measurement.

User control 1422 may include one or more rotary knobs, buttons,keypads, sliders, and/or other user-activated mechanisms configured tointerface with a user and receive user input. For example, FIG. 14Ashows one embodiment having user control 1422 implemented at least inpart using a rotary knob. In some embodiments, user control 1422 may beimplemented as part of display 1418 or display 1424 configured tofunction as both a user input device and a display device. For example,user control 1422 may be implemented as a graphical user interface (GUI)presented on display 1418 (e.g., a touch screen).

In various embodiments, user control 1422 may receive a user selectionof an operating mode for measurement device 1400, such as a distancemeasurement mode, a wire length measurement mode, or an electrical metermode provided by the respective circuits as described above. In variousembodiments, user control 1422 may further receive various types of userinput described above in connection with various components ofmeasurement device 1400, such input including a selection of electricalparameter type to be measured (e.g., a voltage, a current, a resistance,a capacitance, or other parameter that may be determined by electricalmeter circuit 1514), a selection of a wire gauge number, a referencepropagation speed of a wire, a unit resistance value of a wire, atrigger for distance measurement, a control input for thermal imaging,and/or other inputs as desired for particular applications ofmeasurement device 1400.

Additional components 1526 may include any other device or component asmay be desired for various applications of measurement device 1400. Insome embodiments, additional components 1526 may include motion sensorsimplemented in the same or similar manner as described with regard tomotion sensors 194 in FIG. 1. Such motion sensors may be monitored byand provide information to infrared imaging module 1416 and/or otherrelevant components to perform various NUC techniques described herein.

In some embodiments, additional components 1526 may include apositioning component such as a global positioning system (GPS) moduleadapted to generate geopositional information. The geopositionalinformation obtained through the GPS module may be utilized to annotatethe obtained measurement information and/or thermal images with thelocation of the associated electrical inspection or installation site,for example.

In some embodiments, additional components 1526 may include one or moresensors that may be utilized to detect one or more physical parametersassociated with electrical inspection or installation sites. Forexample, in one embodiment, additional components 1526 may include amoisture sensor (e.g., digital hygrometer) that can measure humidity ormoisture level and convert the measured humidity into suitable signalsthat may be further processed by processor 1519 and/or other suitablecomponents of measurement device 1400. Similarly, the motion sensor, GPSmodule, and other sensors described herein for measurement device 1400may generate suitable sensor signals indicative of the sensed physicalparameters. The sensor signals may be received and further processed bylogic device 1601 of measurement device, according to some embodimentsof the disclosure.

In some embodiments, additional components 1526 may include an indicatorlight (e.g., an LED indicator, a colored light bulb, or otherconventional light sources used to implement indicators), a beeper, achime, a speaker with associated circuitry for generating a tone, orother appropriate devices that may be used to generate an audible and/orvisible notification. Such audible and/or visible indicators may beutilized to inform a user as to a result of measurement or a test, forexample, whether or not a wire is long enough for an installationlocation as described above with respect to display 1418 and memory1520.

In some embodiments, additional components 1526 may include a visiblelight camera implemented with a charge-coupled device (CCD) sensor, acomplementary metal-oxide semiconductor (CMOS) sensor, an electronmultiplying CCD (EMCCD), a scientific CMOS (sCMOS) sensor and/or otherappropriate image sensor to capture visible light images of the scene.Depending on the sensor type, visible light camera may be adapted tocapture electromagnetic radiation in other wavelengths in addition to orinstead of visible light. For example, in some embodiments, the visiblelight camera may be adapted to capture images of near infrared (NIR)and/or short-wave infrared (SWIR) radiation from the electricalinstallation or inspection site (e.g., scene 1540). NIR and SWIR aregenerally referred to as non-thermal infrared. In contrast, someimplementations of infrared imaging module 1416 are adapted to captureMWIR and/or LWIR images (i.e., thermal IR images) as discussed above inconnection with infrared sensors 132. Thus, for some embodiments, imagesof visible light, NIR, and/or SWIR radiation captured by the visiblelight camera may be used to complement MWIR and/or LWIR images capturedby infrared imaging module 1416 as further described herein.

In one embodiment, the visible light camera may be co-located withinfrared imaging module 1416 to form a dual-camera module. In oneexample, infrared imaging module 1416 and the visible light camera maybe implemented as a dual sensor module sharing a common substrateaccording to various techniques described in U.S. Provisional PatentApplication No. 61/748,018 previously referenced herein. Such a dualsensor module implementation may include common circuitry and/or commonrestraint devices for infrared imaging and visible light imaging,thereby potentially reducing an overall size of measurement device 1400as compared to embodiments where infrared imaging module 1416 and thevisible light camera are implemented as individual modules.Additionally, the dual sensor module implementation may be adapted toreduce a parallax error between images captured by infrared imagingmodule 1416 and the visible light camera by spacing them closertogether.

In another embodiment, the visible light camera may be attached,mounted, installed, plugged in or otherwise disposed at a suitablelocation separate from infrared imaging module 1416. In someembodiments, visible light images captured by the visible light cameramay be fused, superimposed, or otherwise combined with the thermalimages captured by infrared imaging module 1416 to generateuser-viewable thermal images with higher definition, clarity, and/orcontrast using appropriate techniques as further described herein withreference to FIG. 19 and elsewhere.

In some embodiments, measurement device 1400 described above may beconveniently carried by electricians or other users to work sites, andutilized by such users to perform various measurements and inspectionsin an integrated manner without requiring users to use multipledifferent devices or write down intermediate measurements. Further, thethermal images captured and presented by measurement device 1400 mayadvantageously aid users in quickly scanning the work site forelectrical and other faults, as well as in accurately and convenientlyaiming optical beams to perform distance measurement.

FIG. 16 illustrates a block diagram of another embodiment of ameasurement device 1600. As shown, measurement device 1600 may includevarious components described above for measurement device 1400 anddenoted by like reference numerals. Measurement device 1600 may alsoinclude a housing 1602, a non-contact electrical sensor 1604, additionalmeasurement components 1611, a wireless communication module 1613, anon-thermal imaging module 1626, a moisture sensor 1627, and/oradditional sensors 1629.

Non-contact electrical sensor 1604 may be adapted to sense electricalcurrent, voltage, and/or other electrical parameters associated with aconductor without making a physical electrical contact with theconductor. For example, non-contact electrical sensor 1604 may beimplemented with an inductive sensor comprising a Rogowski coil, an iron(or ferrite) core current transformer, or other appropriate transducercapable of sense AC current. In some embodiments, non-contact electricalsensor 1604 may comprise a Hall effect sensor that allows both AC and DCsensing. In some embodiments, non-contact electrical sensor 1604 maycomprise a coil or transducer configured for sensing voltage associatedthe conductor via a capacitive coupling technique known in the art.Thus, non-contact electrical sensor 1604 may be provided in addition toor instead of electrical terminals 1404, to sense electrical parameterswithout a need for electrical terminals 1404 and test leads 1530. Forembodiments having non-contact electrical sensor 1604, processor 1519and/or electrical meter circuit 1514 may be adapted to convert theparameters sensed via non-contact electrical sensor 1604 intoappropriate measurement values.

In some embodiments, non-contact electrical sensor 1604 may be providedin a clamp that can be opened and closed by a user of measurement device1600, so that the conductor can be at least partially encircled by theclamp for measuring. In some embodiments, non-contact electrical sensor1604 may be provided in a flexible loop having at least one end that isdetachable to allow the loop to encircle the conductor to be measured.It is also contemplated that non-contact electrical sensor 1604 may beprovided in other forms and/or structures suitable for non-contactsensing of various electrical parameters associated with the conductor.

In some embodiments, the clamp, flexible loop, or other structurecomprising the non-contact electrical sensor 1604 may be detachable orseparate from housing 1602. Non-contact electrical sensor 1604 for suchembodiments may be placed at a distance from a user holding housing 1602that contains other components of measurement device 1600, therebypermitting the user to remain at a safe stand-off distance whileobtaining electrical measurements from potentially dangerous components.In such embodiments, the clamp, flexible loop, or other structurecomprising the non-contact electrical sensor 1604 may be further adaptedto wirelessly transmit sensed or measured electrical parameters to othercomponents (e.g., processor 1519) of measurement device 1600 for furtherprocessing and/or displaying to the user.

It is contemplated that other components of measurement device 1600 mayalso be configured to allow remote measurement in a similar manner. Forexample, moisture sensor 1627 and its supporting circuitry if any may beprovided in their own housing that is detachable or separate fromhousing 1602, and configured to wirelessly transmit sensed or measuredmoisture level. In another example, all or part of electrical metercircuit 1514 and electrical terminals 1404 may be provided in their ownhousing detachable or separate from housing 1602, and configured towirelessly transmit sensed or measured electrical parameters associatedwith a component electrically connected to terminals 1404 via test leads1530.

In this regard, measurement device 1600 in some embodiments may includewireless communication module 1613 adapted to handle, manage, orotherwise facilitate wireless communication (e.g., via wireless link1670) between such detachable or separate sensors and other componentsof measurement device 1600. For example, wireless communication modulemay include components to implement the IEEE 802.11 WiFi standards, theBluetooth™ standard, the ZigBee™ standard, or other appropriate shortrange wireless communication standards. Wireless communication module1613 may also be configured for a proprietary wireless communicationprotocol and interface based on radio frequency (RF), microwavefrequency (MWF), infrared frequency (IRF), and/or other appropriatewireless transmission technologies. Wireless communication module 1613may include an antenna 1676 coupled thereto for wireless communicationpurposes.

In some embodiments, wireless communication module 1613 may be adaptedto handle, manage, or otherwise facilitate wireless communication (e.g.,via wireless link 1672) between measurement device 1600 and a remotedevice 1674. Remote device 1674 may represent, for example, aworkstation computer, a server computer, a tablet computer, a laptopcomputer, a smartphone, another measurement device 1600, or any othersuitable device with wireless communication and data processingcapabilities. In such embodiments, one or more components (e.g.,processor 1519 and/or electric meter circuit 1514) of measurement device1600 may be adapted to wirelessly transmit measurement information,thermal images, non-thermal images, and/or other data (e.g., time andlocation, user notes, or other annotations) generated by measurementdevice 1600 via wireless communication module 1613 to remote device1674, where such measurement information, images, and/or other data maybe further processed and/or stored.

Additional measurement components 1611 may represent optical emitter1406, sensor 1408, distance measurement circuit 1510, and/or lengthmeasurement circuit 1512 described above with reference to FIGS. 14 and15. In various embodiments, one or more of additional measurementcomponents 1611 may optionally be provided in measurement device 1600.

Non-thermal imaging module 1626 may be implemented in a same or similarmanner as the visible light camera of measurement device 1400 describedabove for additional components 1526 of measurement device 1400. Assuch, non-thermal imaging module 1626 may be adapted to capture visiblelight, NIR, and/or SWIR images that may be fused, superimposed, orotherwise combined with the thermal images captured by infrared imagingmodule 1416 to generate user-viewable thermal images with higherdefinition, clarity, and/or contrast using appropriate techniques asfurther describe herein with reference to FIG. 19 and elsewhere.

Moisture sensor 1627 may be provided in some embodiments, andimplemented in a same or similar manner as the moisture sensor ofmeasurement device 1400 described above for additional components 1526of measurement device 1400. Humidity or moisture level measurementobtained with moisture sensor 1627 may be used to verify presence ofwater or moisture in various spots of electrical installation orinspection sites. As discussed above with respect to cold spots 1550B inFIG. 15, a user of measurement device 1600 may scan electricalinstallation or inspection sites to locate cold spots, and then verifypresence of water or moisture in the located cold spots from moisturelevel measurements obtained via moisture sensor 1627. As also discussedabove, moisture sensor 1627 according to some embodiments may be adaptedto wirelessly transmit sensed data to permit remote measurement ofmoisture levels.

Additional sensors 1629 represent one or more other types of sensor thatmay be optionally provided in measurement device 1600. Additionalsensors 1629 may include, for example, an acoustic sensor adapted todetect sound (e.g., sounds from electric arcing) and/or locate sound. Inother examples, additional sensors 1629 may include a vibration sensorand/or a temperature sensor. As discussed above with reference toadditional components 1526 of FIG. 15, sensor signals generated bymoisture sensor 1627 and additional sensors 1429 may be received andfurther processed by logic device 1601 of measurement device, accordingto some embodiments of the disclosure.

As described with reference to FIG. 15, display 1424 may be adapted todisplay user-viewable thermal images from thermal images captured byinfrared imaging module 1416 and/or from images generated by combiningthe thermal images with non-thermal images captured by non-thermalimaging module 1626. In some embodiments, display 1424 may be furtheradapted to display numbers, letters, and/or symbols suitable forpresenting the information generated by measurement device 1600.

For example, processor 1519 and/or display 1424 may be adapted togenerate for display the measured distance, length, and/or electricalparameters in numerical digits, with appropriate letters or symbolsdisplayed to indicate the type of information (e.g., whether the numbersindicate a distance, wire length, voltage, current, resistance, orcapacitance, or other parameter) and the applicable unit (e.g., meters,inches, feet, volts, amperes, ohms, farads, or other units). For furtherexample, processor 1519 and/or display 1424 may be configured togenerate for display, in addition to or instead of a numericalpresentation, a graphical presentation of the information generated bymeasurement device 1600. Such graphical presentation may include, forexample, bar graphs, pie graphs, dials, line graphs, images, graphics orother suitable presentation of corresponding measurement values. In suchembodiments, processor 1519 and/or display 1424 may be adapted tooverlay the generated letters, numbers, symbols, graphics, and/or otherrepresentation of measurement information onto the user-viewable thermalimages when the user-viewable thermal images are also displayed ondisplay 1424.

Turning to FIG. 17, a front exterior view is illustrated of ameasurement device 1600A implemented in accordance with an embodiment ofmeasurement device 1600 of FIG. 16. Measurement device 1600A may includedisplay 1424, where letters, numbers, symbols, graphics, and/or otherrepresentation of measurement information may be displayed and/oroverlaid user-viewable thermal images as discussed above. In the exampleillustration of FIG. 17, display 1424 is showing measurement information1625 overlaid onto a user-viable thermal image 1627. In another aspect,measurement device 1600A may include both infrared imaging module 1416and non-thermal imaging module 1626. As such, various components ofmeasurement device 1600A may be configured to generate enhanceduser-viewable thermal images for display by combining thermal andnon-thermal images as further described herein.

FIG. 18 illustrates a front exterior view of a measurement device 1600Bimplemented in accordance with another embodiment of measurement device1600 of FIG. 16. As shown, measurement device 1600B may include a clamp1604A implementing non-contact electrical sensor 1604. As describedabove for non-contact electrical sensor 1604, clamp 1604A may be openedby a user of measurement device 1600B to at least partially encircleelectrical components (e.g., a conducting wire) for measuring electricalparameters. Measurement device 1600B may include a lever 1660 adapted toopen clamp 1604A when pushed down by a user (e.g., by a lever action). Amotorized actuator, pneumatic actuator, hydraulic actuator, and othersuitable means for opening clamp 1604 are also contemplated for otherembodiments.

Referring now to FIG. 19, a flowchart of a process 1900 to combine orfuse thermal images and non-thermal (e.g., visible light) images isillustrated in accordance with an embodiment of the disclosure. Thecombined images may include radiometric data and/or other thermalcharacteristics corresponding to radiation from electrical inspection orinstallation sites (e.g., scene 1540), but with significantly moreobject detail (e.g., contour or edge detail) and/or contrast thantypically provided by the thermal or non-thermal images alone. Thus, forexample, the combined images generated in these examples maybeneficially provide sufficient radiometric data, detail, and contrastto allow easier recognition and/or interpretation of various electricalcomponents (e.g., wires, circuit breakers, or other electricalcomponents at inspection or installation sites) and potential faultsassociated with them.

Although the process described herein in connection with FIG. 19discusses fusing or combining thermal images with visible light imagesas an example, it should be appreciated that the process may be appliedto combining thermal images with any suitable non-thermal images (e.g.,visible light images, near infrared images, short-wave infrared images,EMCCD images, ICCD images, or other non-thermal images captured bynon-thermal imaging module 1626). Process 1900 may be performed byvarious components of measurement device 1400 or 1600, for example byprocessor 1519, display 1424, infrared imaging module 1416, and/ornon-thermal imaging module 1626.

At block 1902, visible light images and infrared images such as thermalimages may be received. For example, visible light images of scene 1540may be captured by non-thermal imaging module 1626 and the capturedvisible light images may be received by processor 1519. For example,thermal images of scene 1540 may be captured by infrared imaging module1416 and the captured thermal images may be received by processor 1519.Processor 1519 may perform various operations of process 1900 using boththermal images and non-thermal images, for example.

At block 1904, high spatial frequency content from one or more of thevisible light and thermal images may be derived from one or more of thevisible light and thermal images received in block 1902. High spatialfrequency content derived according to various embodiments may includeedge/contour details and/or high contrast pixels extracted from the oneor more of the visible light and thermal images, for example.

In one embodiment, high spatial frequency content may be derived fromthe received images by performing a high pass filter (e.g., a spatialfilter) operation on the images, where the result of the high passfilter operation is the high spatial frequency content. In analternative embodiment, high spatial frequency content may be derivedfrom the received images by performing a low pass filter operation onthe images, and then subtracting the result from the original images toget the remaining content, which is the high spatial frequency content.In another embodiment, high spatial frequency content may be derivedfrom a selection of images through difference imaging, for example,where one image is subtracted from a second image that is perturbed fromthe first image in some fashion, and the result of the subtraction isthe high spatial frequency content. For example, optical elements ofinfrared imaging module 1416 and/or optical elements of non-thermalimaging module 1626 may be configured to introduce vibration,de-focusing, and/or movement artifacts into a series of images capturedby one or both of infrared imaging module 1416 and non-thermal imagingmodule 1626. High spatial frequency content may be derived fromsubtractions of images such as adjacent images in the series.

In some embodiments, high spatial frequency content may be derived fromonly the visible light images or the thermal images. In otherembodiments, high spatial frequency content may be derived from only asingle visible light or thermal image. In further embodiments, highspatial frequency content may be derived from one or more components ofthe visible light and/or thermal mages, such as a luminance component ofvisible light images, for example, or a radiometric component of thermalimages. Resulting high spatial frequency content may be storedtemporarily (e.g., in memory 1520) and/or may be further processedaccording to block 1908.

At block 1906, one or more thermal images may be de-noised. For example,processor 1519 may be configured to de-noise, smooth, or blur one ormore thermal images of scene 1540 using a variety of image processingoperations. In one embodiment, removing high spatial frequency noisefrom the thermal images allows the processed thermal images to becombined with high spatial frequency content derived according to block1904 with significantly less risk of introducing double edges (e.g.,edge noise) to objects depicted in combined images of scene 1540.

In one embodiment, removing noise from the thermal mages may includeperforming a low pass filter (e.g., a spatial and/or temporal filter)operation on the images, where the result of the low pass filteroperation is de-noised or processed thermal images. In a furtherembodiment, removing noise from one or more thermal images may includedown-sampling the thermal images and then up-sampling the images back tothe original resolution.

In another embodiment, processed thermal images may be derived byactively blurring thermal images of scene 1540. For example, opticalelements of infrared imaging module 1416 may be configured to slightlyde-focus one or more thermal images captured by infrared imaging module1416. The resulting intentionally blurred thermal images may besufficiently de-noised or blurred so as to reduce or eliminate a risk ofintroducing double edges into combined images of scene 1540, as furtherdescribed below. In other embodiments, blurring or smoothing imageprocessing operations may be performed by processor 1519 on the receivedthermal images as an alternative or supplement to using optical elementsto actively blur thermal images of scene 1540. Resulting processedthermal images may be stored temporarily (e.g., in memory 1520) and/ormay be further processed according to block 1908.

At block 1908, high spatial frequency content may be blended with one ormore thermal images. For example, processor 1519 may be configured toblend high spatial frequency content derived in block 1904 with one ormore thermal images of scene 1540, such as the processed thermal imagesprovided in block 1906.

In one embodiment, high spatial frequency content may be blended withthermal images by superimposing the high spatial frequency content ontothe thermal images, where the high spatial frequency content replaces oroverwrites those portions of the thermal images corresponding to wherethe high spatial frequency content exists. For example, the high spatialfrequency content may include edges of objects depicted in images ofscene 1540, but may not exist within the interior of such objects. Insuch embodiments, blended image data may simply include the high spatialfrequency content, which may subsequently be encoded into one or morecomponents of combined images, as described in block 1910.

For example, a radiometric component of thermal images may be achrominance component of the thermal images, and the high spatialfrequency content may be derived from the luminance and/or chrominancecomponents of visible light images. In this embodiment, combined imagesmay include the radiometric component (e.g., the chrominance componentof the thermal images) encoded into a chrominance component of thecombined images and the high spatial frequency content directly encoded(e.g., as blended image data but with no thermal image contribution)into a luminance component of the combined images. By doing so, aradiometric calibration of the radiometric component of the thermalimages may be retained. In similar embodiments, blended image data mayinclude the high spatial frequency content added to a luminancecomponent of the thermal images, and the resulting blended data encodedinto a luminance component of resulting combined images.

In other embodiments, high spatial frequency content may be derived fromone or more particular components of one or a series of visible lightand/or thermal images, and the high spatial frequency content may beencoded into corresponding one or more components of combined images.For example, the high spatial frequency content may be derived from aluminance component of visible spectrum images, and the high spatialfrequency content, which in this embodiment is all luminance image data,may be encoded into a luminance component of combined images.

In another embodiment, high spatial frequency content may be blendedwith thermal images using a blending parameter and an arithmeticequation. For example, in one embodiment, the high spatial frequencycontent may be derived from a luminance component of visible lightimages. In such an embodiment, the high spatial frequency content may beblended with a corresponding luminance component of thermal imageaccording to a blending parameter and a blending equation to produceblended image data. The blended image data may be encoded into aluminance component of combined images, for example, and the chrominancecomponent of the thermal images may be encoded into the chrominancecomponent of the combined images. In embodiments where the radiometriccomponent of the infrared images may be their chrominance component, thecombined images may retain a radiometric calibration of the thermalimages. In other embodiments, portions of the radiometric component maybe blended with the high spatial frequency content and then encoded intocombined images.

More generally, the high spatial frequency content may be derived fromone or more components of visible light images and/or thermal image. Insuch an embodiment, the high spatial frequency content may be blendedwith one or more components of the thermal images to produce blendedimage data (e.g., using a blending parameter and a blending equation),and resulting combined images may include the blended image data encodedinto corresponding one or more components of the combined images. Insome embodiments, the one or more components of the blended data do nothave to correspond to the eventual one or more components of thecombined images (e.g., a color space/format conversion may be performedas part of an encoding process).

A blending parameter value may be selected by a user or may beautomatically determined by processor 1519 according to context or otherdata, for example, or according to an image enhancement level expectedby measurement device 1400/1600. In some embodiments, the blendingparameter may be adjusted or refined while combined images are beingdisplayed (e.g., by display 1424). In some embodiments, a blendingparameter may be selected such that blended image data includes onlythermal characteristics, or, alternatively, only visible lightcharacteristics. A blending parameter may also be limited in range, forexample, so as not to produce blended data that is out-of-bounds withrespect to a dynamic range of a particular color space/format or adisplay.

In addition to or as an alternative to the processing described above,processing according to the high contrast mode may include one or moreprocessing steps, ordering of processing steps, arithmetic combinations,and/or adjustments to blending parameters as disclosed in U.S. patentapplication Ser. No. 13/437,645 previously referenced herein. Forexample, the following equations may be used to determine the componentsY, Cr and Cb for the combined images with the Y component from the highpass filtered visible light images and the Cr and Cb components from thethermal images.

hp_(—) y_vis=highpass(y_vis)

(y_ir,cr_ir,cb_ir)=colored(lowpass(ir_signal_linear))

In the above equations, highpass(y_vis) may be high spatial frequencycontent derived from high pass filtering a luminance component ofvisible light images.

Colored(lowpass(ir_signal_linear)) may be the resulting luminance andchrominance components of the thermal images after the thermal imagesare low pass filtered. In some embodiments, the thermal images mayinclude a luminance component that is selected to be 0.5 times a maximumluminance (e.g., of a display and/or a processing step). In relatedembodiments, the radiometric component of the thermal images may be thechrominance component of the thermal images. In some embodiments, they_ir component of the thermal images may be dropped and the componentsof the combined images may be (hp_y_vis, cr_ir, cb_ir), using thenotation above.

In another embodiment, the following equations may be used to determinethe components Y, Cr and Cb for combined images with the Y componentfrom the high pass filtered visible light images and the Cr and Cbcomponents from the thermal images.

comb_(—) y=y_ir+alpha×hp_(—) y_vis

comb_(—) cr=cr_ir

comb_(—) cb=cb_ir

The variation of alpha thus gives the user an opportunity to decide howmuch contrast is needed in the combined images. With an alpha of closeto zero, the thermal images alone will be shown, but with a very highalpha, very sharp contours/edges can be seen in the combined images.Theoretically, alpha can be an infinitely large number, but in practicea limitation will probably be necessary, to limit the size of alpha thatcan be chosen to what will be convenient in the current application.

Once the high spatial frequency content is blended with one or morethermal images, processing may proceed to block 1610, where blended datamay be encoded into components of the combined images in order to formthe combined images.

At block 1910, the blended data may be encoded into one or morecomponents of the combined images. For example, processor 1519 may beconfigured to encode blended data derived or produced in accordance withblock 1910 into combined images that increases, refines, or otherwiseenhances the information conveyed by either the visible light or thermalimages viewed by themselves. In some embodiments, encoding blended imagedata into a component of combined images may include additional imageprocessing operations, for example, such as dynamic range adjustment,normalization, gain and offset operations, noise reduction, and colorspace conversions, for instance.

In addition, processor 1519 may be configured to encode other image datainto combined images. For example, if blended image data is encoded intoa luminance component of combined images, a chrominance component ofeither visible light images or thermal images may be encoded into achrominance component of combined images. Selection of source images maybe made through user input, for example, or may be determinedautomatically based on context or other data. More generally, in someembodiments, a component of combined images that is not encoded withblended data may be encoded with a corresponding component of visiblelight images or thermal images. By doing so, a radiometric calibrationof thermal images and/or a color space calibration of visible lightimages may be retained in the resulting combined images.

In some embodiments, at least some part or some functionalities ofprocessor 1519 described herein may be implemented as part of infraredimaging modules 1416, for example, at processing module 160 describedabove in connection with FIG. 3. In some embodiments, at least some partor some functionalities of processor 1519 may be part of or implementedwith processing components of display 1418 and/or display 1424.

Referring now to FIG. 20, a flowchart of a process 2000 to performmeasurements and inspections using a measurement device is illustratedin accordance with an embodiment of the disclosure. For example, process2000 may be performed by in part by various embodiments of measurementdevice 1400 and in part by a user utilizing various embodiments ofmeasurement device 1400. Although certain portions of process 2000 aredescribed below with respect to measuring, installing, and inspectingoperations in electrical wire installation tasks, it should be notedthat various operations of process 2000 may be reordered, omitted,and/or combined to perform other tasks as well.

At block 2002, measurement device 1400 is suitably positioned and aimedto measure a distance associated with an installation location. Forexample, a user may position (e.g., while held by a hand of the user)measurement device 1400 at one end of an installation location and aimoptical emitter 1406 toward the other end of the installation locationso that the distance between the two ends may be measured. In oneembodiment, thermal images including visual guidance information may becaptured and generated by performing operations described above withrespect to infrared imaging module 1416. In such an embodiment, a usermay view user-viewable thermal images, which may include an aimingreticle/cross-hair and/or an image of a reflected optical beam, toaccurately aim the optical beam from optical emitter 1406 to the otherend of the installation location.

At block 2004, a distance measurement mode is selected as an operatingmode of measurement device 1400. For example, the user may input orotherwise provide a selection of a distance measurement mode on usercontrol 1422 of measurement device 1400. Appropriate components ofmeasurement device 1400 may determine a distance as described for blocks2006-2008 below. Selection of a distance measurement mode may beperformed prior to performing operations of block 2002, as needed ordesired for particular applications of process 2000.

At block 2006, an optical beam may be transmitted to and reflected fromthe other end of the installation location. For example, if aimedcorrectly at block 2002, distance measurement circuit may transmit anoptical beam to the other end of the installation location using opticalemitter 1406. As described above, the optical beam may be transmitted invarious forms, patterns and/or wavelengths. If there is no suitablesurface or target from which the optical beam may reflect off at theother end of the installation location, a suitable target object (e.g.,any object that sufficiently reflects the optical beam) may be placed atthe other end of the installation location by the user.

At block 2008, the distance between the two ends of the installationlocation may be determined based on the reflected optical beam. Forexample, based on a detection signal generated by sensor 1408, distancemeasurement circuit 1510 may determine the distance by performing atime-of-flight distance calculation or phase-shift detection operationas described above with respect to optical emitter 1406, sensor 1408,and distance measurement circuit 1510. The determined distance may thenbe displayed and/or stored at block 2010. For example, the determineddistance may be presented on display 1418 or display 1424 for viewing bythe user. In some embodiments, the determined distance may be stored inmemory 1520 for displaying and/or further processing as described abovein connection with display 1418 and memory 1520. In some embodiments,blocks 2002, 2006, 2008, and 2010 may be repeated to obtain an aggregatespan of the installation location, for example, when there are bends andturns in the installation location. As described above, variouscomponents of measurement device 1400 may calculate a sum of multiplemeasurements to provide an aggregate span.

At block 2012, a wire to be cut and installed at the installationlocation may be connected to measurement device 1400 to determine thelength of the wire. For example, the user may connect one or both endsof wire 1534 to appropriate ones of terminals 1404 to electricallyconnect wire 1534 to length measurement circuit 1512. As discussed, someimplementations of length measurement circuit 1512 may operate usingelectrical connections to both ends 1534A and 1534B of wire 1534,whereas other implementations may operate using only one electricalconnection to end 1534A of wire 1534. Wire 1534 may be connected to theappropriate ones of terminals 1404 with or without test leads 1530 asdesired.

At block 2014, a length measurement mode is selected as the operatingmode of measurement device 1400. For example, the user may input orotherwise provide a selection of a length measurement mode on usercontrol 1422 of measurement device 1400. In some embodiments, a wiregauge number or a propagation speed of the wire to be cut may be input,for example, via user control 1422. Alternatively, a wire segment of aknown length may be connected to the measurement device to obtain anappropriate propagation speed on which to base the wire lengthcalculation as described in connection with length measurement circuit1512.

At block 2016, the length of the wire may be determined. For example, inone embodiment, the length of the wire may be determined using a TDRtechnique as described above with respect to length measurement circuit1512. That is, at block 2016, an electrical pulse may be transmittedthrough wire 1534 via connected end 1534A, and then the electrical pulsereflected at unconnected end 1534B may be detected to determine thelength of the wire. In another embodiment, the length of the wire may bedetermined by measuring a cumulative resistance through wire 1534 withhigh precision, as also described above with respect to lengthmeasurement circuit 1512.

The determined length of the wire to be cut may then be displayed,stored, and/or compared at block 2010. For example, the determinedlength may be presented on display 1418 or display 1424 for viewing bythe user. For example, the determined length may be stored in memory1520 for displaying and/or further processing as described above inconnection with display 1418 and memory 1520. In one embodiment, theuser may compare the determined length of the wire with the determinedspan of the installation location to verify whether the wire is longenough to be cut and installed at the location. In another embodiment,various components of measurement device 1400 may perform the comparisonand generate an indication (e.g., using a beep and/or a light) as towhether the wire is long enough, as described above with respect tomemory 1520 and display 1418 of measurement device 1400.

If the wire is long enough for the location, the user may cut the wireto the desired length, at block 2020. If not, the user may repeat blocks2012, 2016, and 2018 with other wires. Once a wire that is long enoughfor the location is found and cut to the desired length, the length ofthe cut wire may be verified by connecting the cut wire to themeasurement device at block 2022, determining the length of the cut wireat block 2024, and displaying, storing, and/or comparing the length ofthe cut wire at block 2026. Blocks 2022-2026 may be performed in asimilar manner as blocks 2012, 2016, and 2018, except that blocks2022-2026 may be performed with the cut wire, and the comparisonperformed by the user or measurement device 1400 may be to verify thatthe wire is cut to a correct length (e.g., within a certain rangerelative to the correct length) rather than simply check whether thewire is long enough for the installation location.

At block 2028, the cut wire and/or other electrical components may beinstalled at the installation location. For example, the user may, afterverifying that the wire is cut to a correct length at block 2028,install the cut wire along with other electrical components such asswitches, fuses, circuit breakers, distributors, and/or other componentsif desired. Blocks 2002-2028 may be repeated to perform as many wiringtasks as needed.

After the installation of one or more cut wires and/or other components,an infrared camera of measurement device 1400 (e.g., infrared imagingmodule 1416) may be turned on and pointed toward the installationlocation to scan for any abnormal condition, at block 2030. For example,if infrared imaging module 1416 is not already turned on for otherpurposes (e.g., to aim the optical beam at block 2002), the user mayturn on or otherwise activate infrared imaging module 1416 via usercontrol 1422 and point measurement device 1400 toward the installationlocation so that at least a portion of the installation location iswithin scene 1540 captured by infrared imaging module 1416. The user maypoint, position, and/or orient measurement device 1400 to capture anyother scene associated with the user's environment if desired.

At block 2032, thermal images of the installation location or otherscenes associated with the user's environment may be captured, convertedinto user-viewable thermal images, and presented for viewing by theuser. Capturing of the thermal images, as well as generating anddisplaying of the user-viewable thermal images, may be performed usingtechniques described above for infrared imaging module 1416. Forexample, the user-viewable thermal images may be presented on display1418 or display 1424 of measurement device 1400 for viewing by the user,after being converted from the thermal images captured by infraredimaging module 1416. If the measurement device includes a visible lightcamera, visible light images of the installation location or otherscenes may be captured, and suitable operations may be performed on thethermal images and the visible light images to generate combined orfused user-viewable thermal images having a higher definition and/orclarity. Suitable operations for generating fused user-viewable thermalimages may include, for example, resolution and contrast enhancingfusion operations disclosed in U.S. patent application Ser. No.13/105,765, entitled “Infrared Resolution and Contrast Enhancement withFusion” and filed May 11, 2011, which is incorporated herein byreference in its entirety.

At block 2034, the thermal images may be viewed. For example, the usermay view the user-viewable thermal images of the installation locationor other scenes on display 1418 or display 1424 of measurement device1400 to scan for hot spots 1550A, cold spots 1550B, or any otherindication of faults. Because poor connections, corroded connections,incorrectly secured connections, internal damages, unbalanced loads, andother various electrical faults typically exhibit higher or lowertemperature than normally operating wires and/or components, likelyfaulty wires and/or components may be quickly detected by viewing theuser-viewable thermal images. Such suspect wires, components, and/orother external articles may be connected to the measurement device atblock 2036 to check various electrical parameters (e.g., voltage,current, resistance, capacitance, and/or other parameter) associatedwith the wires, components, and/or other external articles. For example,the user may connect external article 1532 to appropriate ones ofterminals 1404 to electrically connect external article 1532 toelectrical meter circuit 1514. Test leads 1530 may be selectively usedas desired.

At block 2038, an electrical meter mode is selected as the operatingmode of measurement device 1400. For example, the user may input orotherwise provide a selection of an electrical meter mode on usercontrol 1422 of measurement device 1400. In some embodiments, the usermay further select one of a voltage, a current, a resistance, acapacitance, or other electrical parameter to be measured, for example,via user control 1422. Selection of an electrical meter mode may beperformed prior to connecting wires, components, and/or other externalarticles at block 2036. At block 2040, an electrical parameterassociated with the suspect wires, components, and/or other externalarticles may be determined using conventional techniques. At block 2042,the determined electrical parameter may be presented for viewing by theuser, for example, on display 1418 by performing operations describedabove with respect to display 1418 of measurement device 1400. The usermay view the presented electrical parameter to verify or furtherdiagnose any fault that may be present in the suspect wires, components,and/or other external articles. If measurement of more than oneelectrical parameter is needed or desired, the user may select anotherelectrical parameter, for example, on user control 1422, and blocks2040-2042 may be repeated.

Referring now to FIG. 21, a flowchart of a process 2100 to manufacture ameasurement device is illustrated in accordance with an embodiment ofthe disclosure. For example, measurement device 1400/1600 or othersimilar devices may be constructed by performing all or part of process2100. In various embodiments, various operations of process 2100 may bereordered, combined, modified and/or omitted as desired for particularapplications of process 2100, such as to manufacture various embodimentsof measurement device 1400/1600 or other similar devices. Althoughparticular locations, placements, and orientations are described forvarious components of measurement device 1400/1600, these may beadjusted in other embodiments as may be desired for variousimplementations.

At block 2102, housing 1402/1602 for measurement device 1400/1600 may beprovided. Housing 1402/1602 may be shaped and sized to be hand-held orotherwise conveniently handled by a user (e.g., an electrician) whenbeing carried or used in field operation. For example, in oneembodiment, housing 1402/1602 may be of a similar size and shape asillustrated for housing 1602A or 1602B in FIGS. 17 and 18. In someembodiments, a handle or other protrusion (e.g., a pistol grip) may beprovided on housing 1402/1602, so as to allow the user to comfortablyhold housing 1402/1602. Housing 1402/1602 may be made of any materialsuitable to protect internal components in field use. In one embodiment,housing 1402/1602 may be made of a combination of durable polymer andmetal. Housing 1402/1602 may be manufactured by any suitable combinationof molding, assembling, forging, and other applicable constructiontechniques.

At block 2104, electrical terminals 1404 may be provided. For example,electrical terminals 1404 may be arranged on any one or more of theexterior surfaces of housing 1402/1602, at any location that allowsconvenient electrical connection to wires and/or external articles, asdescribed above with respect to FIGS. 14A-15. In one embodiment,receptacles, sockets, plugs, pins, clips, screws, or other structuresused to implement electrical terminals 1404 may be mounted, installed,or otherwise placed in apertures may be formed at appropriate locationson housing 1402/1602. Such structures may be made of conductivematerial, so that electrical terminals 1404 may form an electricalconnection to external wires, cables, or articles when received in theconnection mechanisms. In one embodiment, such structures may insertablyand/or releasably receive a test lead (e.g., test lead 1530) which mayinclude a standard or proprietary connector. In some embodiments,non-contact electrical sensor 1604 may be provided in clamp 1604A orflexible loop at block 2104. Clamp 1604A, the flexible loop, or otherstructure housing non-contact electrical sensor 1604 may be detachablyprovided depending on the embodiments.

At block 2106, optical emitter 1406 may be provided. In variousembodiments, optical emitter 1406 may be mounted on, installed in,attached to, or otherwise fixed relative to housing 1402, such thatoptical emitter 1406 may transmit an optical beam without being coveredor blocked by housing 1402. Optical emitter 1406 may be orientedrelative to housing 1402 such that the optical beam may be aimed by auser holding and pointing housing 1402 toward a desired direction. Forexample, in one embodiment, at least a portion of optical emitter 1406may be exposed and positioned on a top side of housing 1402 asillustrated in FIGS. 14A-14B, such that a user may point the top side ofhousing 1402 toward a desired direction to aim an optical beamtransmitted from optical emitter 1406.

At block 2108, sensor 1408 may be provided at a location suitable fordetecting a reflected optical beam. In various embodiments, sensor 1408may be mounted on, installed in, attached to, or otherwise fixed onhousing 1402 at a location that may be reached by the optical beamreflected from an external target (e.g., target 1542). For example, inone embodiment, at least a portion of sensor 1408 may be exposed andpositioned on the same top side of housing 1402 as optical emitter 1406,as illustrated in FIG. 14B. As may be appreciated, sensor 1408 need notbe perfectly aligned with optical emitter 1406, since the reflectedoptical beam may typically be diffused in all directions. As such,sensor 1408 may be positioned at any suitable location that may bereached by the reflected optical beam.

At block 2110, distance measurement circuit 1510 may be provided. Invarious embodiments, distance measurement circuit 1510 may be providedon a circuit board or other packaging, which may be substantiallyenclosed within, placed substantially in an interior of, or otherwisefixed relative to housing 1402, such that housing 1402 may provide todistance measurement circuit 1510 at least some protection from anexternal environment. Thus, for example, an appropriate combination ofanalog circuits, digital circuits, and/or memory devices (e.g., memory1520) implementing distance measurement circuit 1510 may be provided ona circuit board or other suitable packaging that is substantiallyenclosed within, placed substantially in an interior of, or otherwisefixed relative to the housing.

At block 2112, distance measurement circuit 1510 may be communicativelycoupled to optical emitter 1406 and sensor 1408. In various embodiments,suitable circuit board traces, buses, wires, cables, ribbon connectors,and/or other connectors may be provided and utilized to form signalpaths suitable for transmitting analog and/or digital signals (e.g.,including electric transmissions, optical transmissions, or otherappropriate carriers for signals) between distance measurement circuit1510 and optical emitter 1406, and between distance measurement circuit1510 and sensor 1408.

At block 2114, electrical meter circuit 1514 may be provided. In variousembodiments, electrical meter circuit 1514 may be provided on a circuitboard or other packaging, which may be substantially enclosed within,placed substantially in an interior of, or otherwise fixed relative tohousing 1402/1602, such that housing 1402/1602 may provide to electricalmeter circuit 1514 at least some protection from an externalenvironment. In some embodiments, electrical meter circuit 1514 may beprovided on the same circuit board or other packaging as distancemeasurement circuit 1510, and may also share some components withdistance measurement circuit 1510 depending on the embodiment.Electrical meter circuit 1514 may be implemented using an appropriatecombination of analog circuits, digital circuits, and/or memory devices(e.g. memory 1520), as described above with respect to FIGS. 14A-15.

At block 2116, electrical meter circuit 1514 may be electricallyconnected to one or more of electrical terminals 1404 and/or non-contactelectrical sensor 1604. In various embodiments, circuit board traces,cables, wires, and/or suitable other connection may be provided betweenelectrical meter circuit 1514 and the appropriate ones of electricalterminals 1404, such that electrical paths may be formed with sufficientpower ratings for desired applications of measurement device 1400. Insome embodiments, the electrical connections may be non-switchable, suchthat electrical terminals 1404 may each be assigned a specific type ofinput (e.g., a terminal for voltage measurement, a terminal for currentmeasurement, a terminal for ground connection, or a terminal for othertype of input). In other embodiments, the electrical connections may berouted to an automatic or manual switch circuit, which may be providedas part of electrical meter circuit 1514, as part of user control 1422,or as a separate component. In such embodiments, electrical terminals1404 may be switchable (e.g., by automatic sensing and/or receivingmanual selection to adjust a switching circuit) to selectably receivedifferent types of inputs. In yet other embodiments, some of electricalterminals 1404 may be switchable, while other may not be. In variousembodiments, corresponding markings or letterings may be printed,embossed, engraved, or otherwise provided adjacent to each of electricalterminals 1404 on an exterior of housing 1402, so as to indicate whattype of input each of electrical terminals 1404 is wired for. In someembodiments, wireless communication module 1613 may be provided wherenon-contact electrical sensor 1604 is detachably provided.

At block 2118, length measurement circuit 1512 may be provided. Invarious embodiments, length measurement circuit 1512 may be provided ona circuit board or other packaging, which may be substantially enclosedwithin, placed substantially in an interior of, or otherwise fixedrelative to housing 1402, such that housing 1402 may provide to lengthmeasurement circuit 1512 at least some protection from an externalenvironment. In some embodiments, length measurement circuit 1512 may beprovided on the same circuit board or other packaging as distancemeasurement circuit 1510 and/or electrical meter circuit 1514. In someembodiments, length measurement circuit 1512 may also share somecomponents with distance measurement circuit 1510 and/or electricalmeter circuit 1514. Length measurement circuit 1512 may be implementedusing an appropriate combination of analog circuits, digital circuits,and/or memory devices (e.g., memory 1520), as described above withrespect to FIGS. 14A-15.

At block 2120, length measurement circuit 1512 may be electricallyconnected to one or more of electrical terminals 1404. In variousembodiments, circuit board traces, cables, wires, and/or suitable otherconnection may be provided between length measurement circuit 1512 andthe appropriate ones of electrical terminals 1404, such that electricalpaths may be formed with sufficient power ratings for desiredapplications of measurement device 1400. In various embodiments, theelectrical connections may be wired, routed, or otherwise formed to benon-switchable or switchable, in a similar manner as described for block2116. In some embodiments, the electrical connections may be wired,routed, or otherwise formed to share at least one of electricalterminals 1404 with electrical meter circuit 1514.

At block 2122, display 1418 may be provided. In various embodiments,display 1418 may be mounted on, installed in, attached to, or otherwisefixed on housing 1402/1602, and may have at least a readout panel (e.g.,a VFD panel, LED panel, or other multi-segment or dot-matrix panel) oran electronic display screen (e.g., a LCD screen) portion exposed on anexterior surface of housing 1402. For example, in one embodiment,display 1418 may be positioned or otherwise fixed relative to housing1402/1602, such that the readout panel portion is exposed on the frontsurface of housing 1402/1602 for viewing by a user, as illustrated inFIG. 14A, 17, or 18. Display 1418 may be implemented using a readoutpanel or electronic screen, a display processor, and/or a memory device(e.g., memory 1520), as described above with respect to FIGS. 14A-15.

At block 2124, display 1418 may be communicatively coupled to distancemeasurement circuit 1510, electrical meter circuit 1514, lengthmeasurement circuit 1512, and/or other components of measurement device1400/1600. In various embodiments, suitable circuit board traces, buses,wires, cables, ribbon connectors, and/or other connectors may beprovided between display 1418 and various components of measurementdevice 1400/1600 to form signal paths suitable for transmitting analogand/or digital signals that may encode information indicative of thevarious measurements determined by the respective circuits. In someembodiments, blocks 2122 and 2124 may be omitted where display 1424 maybe configured to present both measurement information and user-viewablethermal images.

At block 2126, user control 1422 may be provided. In variousembodiments, user control 1422 may be disposed on, mounted on, orotherwise fixed relative to housing 1402/1602, such that rotary knobs,buttons, keypads, sliders, and/or other user-activated input mechanismsmay be exposed on an exterior surface of housing 1402/1602 to receiveinterface with and receive input from a user. For example, a rotary knobor other user-activate input mechanism of user control 1422 may beexposed on the front exterior of housing 1402/1602 with appropriateletterings or markings, as illustrated in FIG. 14A, 17, or 18. Invarious embodiments, user control 1422 may be communicatively coupled(e.g., connected using appropriate circuit board traces, buses, wires,cables, ribbon connectors, and/or other connections suitable fortransmitting analog and/or digital signals) to various componentsincluding distance measurement circuit 1510, electrical meter circuit1514, and/or length measurement circuit 1512. In some embodiments, block2126 may be omitted where user control 1422 may be implemented as a GUIpresent on display 1418 or display 1424.

At block 2128, infrared imaging module 1416 may be installed. In variousembodiments, infrared imaging module 1416 may be mounted on, installedin, or attached to housing 1402/1602 at a location that suitablyprovides infrared imaging module 1416 with an unobstructed view to ascene (e.g., scene 1540). In some embodiments, infrared imaging module1416 may be oriented relative to optical emitter 1406 such that theimpingement point of the optical beam from optical emitter may be placedwithin FOV 1541 of infrared imaging module 1416. For example, in oneembodiment, at least a lens or other aperture to an FPA of infraredimaging module 1416 may be exposed and positioned on a top side ofhousing 1402 next to optical emitter 1406, as illustrated in FIGS.14A-14B. In one embodiment, infrared imaging module 1416 may be receivedand secured in place by a socket, such as socket 104 described abovewith respect to FIGS. 1-2. In one embodiment, appropriate pins, tabs,plugs, or other fasteners may be provided to releasably attach infraredimaging module 1416 implemented as a plug-in unit (e.g., an add-onmodule). In some embodiments, non-thermal imaging module 1626 may beinstalled in a manner similar to infrared imaging module 1416. In someembodiments, infrared imaging module 1416 and non-thermal imaging module1626 may be provided together in a dual sensor module and installedtogether.

At block 2130, a display screen (e.g., display 1424) may be provided. Invarious embodiments, display 1424 may be mounted on, installed in,attached to, or otherwise fixed on housing 1402/1602, and may have atleast an electronic display screen (e.g., a LCD screen) portion exposedon an exterior surface of housing 1402/1602. For example, in oneembodiment, display 1424 may be positioned or otherwise fixed relativeto the housing, such that the electronic display screen portion isexposed on the front surface of housing 1402/1602 for viewing by a user,as illustrated in FIG. 14A, 17, or 18. In some embodiments, block 2130may be omitted where only one display 1418 is provided.

At block 2132, the display screen (e.g., display 1424) may becommunicatively coupled to infrared imaging module 1416 and/or othercomponents of measurement device 1400/1600. In various embodiments,suitable circuit board traces, buses, wires, cables, ribbon connectors,and/or other connectors may be provided between screen and infraredimaging module 1416 to form signal paths suitable for transmittinganalog and/or digital signals that may encode raw or user-viewablethermal images captured and/or generated by infrared imaging module1416. In embodiments where display 1418 may be configured to presentuser-viewable thermal images, display 1418 may be communicativelycoupled to infrared imaging module 1416.

Where applicable, various embodiments provided by the present disclosurecan be implemented using hardware, software, or combinations of hardwareand software. Also where applicable, the various hardware componentsand/or software components set forth herein can be combined intocomposite components comprising software, hardware, and/or both withoutdeparting from the spirit of the present disclosure. Where applicable,the various hardware components and/or software components set forthherein can be separated into sub-components comprising software,hardware, or both without departing from the spirit of the presentdisclosure. In addition, where applicable, it is contemplated thatsoftware components can be implemented as hardware components, andvice-versa.

Software in accordance with the present disclosure, such asnon-transitory instructions, program code, and/or data, can be stored onone or more non-transitory machine readable mediums. It is alsocontemplated that software identified herein can be implemented usingone or more general purpose or specific purpose computers and/orcomputer systems, networked and/or otherwise. Where applicable, theordering of various steps described herein can be changed, combined intocomposite steps, and/or separated into sub-steps to provide featuresdescribed herein.

Embodiments described above illustrate but do not limit the invention.It should also be understood that numerous modifications and variationsare possible in accordance with the principles of the invention.Accordingly, the scope of the invention is defined only by the followingclaims.

What is claimed is:
 1. A measurement device comprising: a housingadapted to be hand-held by a user; a logic device adapted to determine aphysical parameter associated with an external article; an infraredimaging module adapted to capture an infrared image of a scene; and adisplay fixed relative to the housing and adapted to overlay informationindicative of the physical parameter onto a user-viewable image,converted from the captured infrared image, to display the informationand the user-viewable image for viewing by the user.
 2. The measurementdevice of claim 1, wherein: the physical parameter comprises anelectrical parameter; and the logic device comprises an electrical metercircuit adapted to be electrically connected to the external article todetermine the electrical parameter.
 3. The measurement device of claim1, further comprising a sensor adapted to generate a sensor signalindicative of the physical parameter, wherein the logic device isadapted to determine the physical parameter in response to the sensorsignal.
 4. The measurement device of claim 3, wherein: the physicalparameter comprises an electrical parameter; the sensor comprises anon-contact electrical sensor adapted to sense the electrical parameterassociated with the external article without making electrical contact;and the logic device is adapted to determine the electrical parameter inresponse to the sensor signal from the non-contact electrical sensor. 5.The measurement device of claim 4, wherein the non-contact electricalsensor comprises a clamp adapted to at least partially encircle theexternal article for sensing the electrical parameter.
 6. Themeasurement device of claim 4, wherein the non-contact electrical sensoris detachable from the housing and adapted to wirelessly transmit thesensor signal to the logic device, the measurement device furthercomprising a wireless communication module adapted to facilitatewireless communication between the non-contact electrical sensor and thelogic device.
 7. The measurement device of claim 3, wherein: thephysical parameter comprises a humidity level; the sensor comprises amoisture sensor that is responsive to moisture; and the logic device isadapted to determine the humidity level in response to the sensor signalfrom the moisture sensor.
 8. The measurement device of claim 1, furthercomprising a non-thermal imaging module adapted to capture a non-thermalimage of the scene, wherein: the infrared image captured by the infraredimaging module is a thermal image; and the logic device is adapted tocombine the thermal and the non-thermal images to generate theuser-viewable thermal image.
 9. The measurement device of claim 8,further comprising: an optical emitter configured to transmit a laserbeam to a target in the scene; a sensor configured to detect the laserbeam as reflected from the target and to generate a detection signal inresponse to the detected laser beam, wherein the logic device is adaptedto determine a distance to the target based on the detection signal, andwherein the logic device is further adapted to: derive high spatialfrequency content from the non-thermal image, and combine the thermaland the non-thermal images by adding the high spatial frequency contentto the thermal image to improve contrast and edge detail in theuser-viewable image.
 10. A measurement device comprising: a housingconfigured to be hand-held by a user; an optical emitter configured totransmit an optical beam to a target in a scene; a sensor configured todetect the optical beam as reflected from the target and to generate adetection signal in response to the detected optical beam; a distancemeasurement circuit configured to determine a distance to the targetbased on the detection signal; an electrical meter circuit configured tobe electrically connected to an external article and to determine anelectrical parameter associated with the external article; and a displayconfigured to present information indicative of the distance and/or theelectrical parameter for viewing by the user.
 11. The measurement deviceof claim 10, further comprising a length measurement circuit configuredto be electrically connected to a wire and to determine a length of thewire, wherein the display is further configured to present informationindicative of the length of the wire for viewing by the user.
 12. Themeasurement device of claim 10, further comprising an infrared imagingmodule configured to capture an infrared image of the scene, wherein thedisplay is further configured to: present the infrared image for viewingby the user; and overlay the information indicative of the distanceand/or the electrical parameter onto the infrared image.
 13. Themeasurement device of claim 12, wherein the infrared image comprises animage of the optical beam.
 14. The measurement device of claim 12,further comprising a non-thermal imaging module configured to capture anon-thermal image of the scene, wherein: the infrared image is a thermalimage; and the display is further configured to combine the thermal andthe non-thermal images to generate a combined image for viewing by theuser.
 15. The measurement device of claim 14, wherein: the infraredimaging module comprises a focal plane array (FPA) configured to capturethe infrared image of the scene; the FPA comprises an array ofmicrobolometers adapted to receive a bias voltage selected from a rangeof approximately 0.2 volts to approximately 0.7 volts; and the displayis further configured to derive high spatial frequency content from thenon-thermal image and to combine the thermal and the non-thermal imagesby adding the high spatial frequency content to the thermal image toimprove contrast and edge detail in the combined image.
 16. A methodcomprising: transmitting an optical beam to a target using an opticalemitter of a measurement device configured to be hand-held by a user,wherein the optical beam is aimed at the target by the user; detectingthe optical beam as reflected off the target using a sensor of thedevice; generating a detection signal in response to the detectedoptical beam; determining, by a distance measurement circuit of thedevice, a distance to the target based on the detection signal;presenting, for viewing by the user on a display of the device,information indicative of the distance to the target; determining, by anelectrical meter circuit of the device, an electrical parameter of anexternal article electrically connected to the electrical meter circuit;and presenting, for viewing by the user on the display, informationindicative of the electrical parameter.
 17. The method of claim 16,further comprising: determining, by a length measurement circuit of thedevice, a length of a wire electrically connected to the lengthmeasurement circuit; and presenting, for viewing by the user on thedisplay, information indicative of the length of the wire.
 18. Themethod of claim 16, further comprising: capturing, at an infraredimaging module of the device, an infrared image of a scene associatedwith an environment of the user; overlaying the information indicativeof the electrical parameter and/or the distance onto the capturedinfrared image; and presenting the infrared image and the overlaidinformation on the display for viewing by the user.
 19. The method ofclaim 18, wherein the infrared image comprises an image of the opticalbeam.
 20. The method of claim 18, wherein the infrared image is athermal image, the method further comprising: capturing, at anon-thermal imaging module of the device, a non-thermal image of thescene; and combining the thermal and the non-thermal images to generatea combined image for viewing by the user.
 21. The method of claim 20,wherein the combining the thermal and the non-thermal images comprises:deriving high spatial frequency content from the non-thermal image; andadding the high spatial frequency content to the thermal image toimprove contrast and edge detail in the combined image.